| To be published Top |
| 299. | Wang, Ziyang, Bin Miao*, Yuming Wang*, Chenglong Shen, Linggao Kong*, Wenya Li, Binbin Tang, Jijie Ma, Fuhao Qiao, Limin Wang, Aibing Zhang, and Lei Li, Analysis of the background signal in Tianwen-1 MINPA, Adv. Space Res., accepted, 2024-07. | |
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| 298. | Chi, Yutian, Chenglong Shen*, Zhiyong Zhang, Mengjiao Xu, Dongwei Mao, Junyan Liu, Can Wang, Bingkun Yu, Jingyu Luo, Zhihui Zhong, and Yuming Wang, Direct observations of a shock interacted with preceding two CMEs: Insights from Solar Orbiter, Wind, and STEREO Observations, Astrophys. J. Lett., accepted, 2024-10. | |
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| 297. | Khuntia, Soumyaranjan*, Wageesh Mishra, Yuming Wang, Sudheer K Mishra, Teresa Nieves-Chinchilla, and Shaoyu Lyu, Deciphering the Evolution of Thermodynamic Properties and their Connection to the Global Kinematics of High-Speed Coronal Mass Ejections Using FRIS Model, Mon. Not. R. Astron. Soc., accepted, 2024-11. | |
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| 296. | Zhou, T. Y., H. S. Fu*, Z. Z. Guo, J. B. Cao, Y. M. Wang, W. D. Fu, and M. Ge, Joint observation of a series of magnetic holes by Tianwen-1 and MAVEN at Mars, Astrophys. J., accepted, 2024-10. | |
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| 295. | Liu, Jiajia, Bingkun Yu, Fuchuan Pang, Siteng Fan, Lixiang Gu, Lingping He, Yajuan Lei, Bo Li, Rui Li, Yiren Li, Dongdong Liu, Kai Liu, Hui Tian, Bo Wang, Yu Wang, Mengjiao Xu, Xianghui Xue, Fei Yan, Xin Ye, Yuming Wang*, and Weiren Wu*, SOTHE: SOlar-Terrestrial Habitability Explorer, Adv. Space Res., accepted, doi:10.1016/j.asr.2024.10.024, 2024-10. [ (1.44MB)] | |
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| 2024 Top |
| 294. | Zhang, Jian, Jingnan Guo*, Yongjie Zhang*, Yihang Cao, Mikhail I. Dobynde, Cunhui Li*, Yuhong Yu, Yuming Wang, Shuwen Tang, Yi Qian, Hongyun Zhao, Zhiyu Sun*, Yi Wang, and Robert F. Wimmer-Schweingruber, The 2022 February 15 Solar Energetic Particle event at Mars: A synergistic study combining multiple radiation detectors on the Surface and in Orbit of Mars with 4 models, Geophys. Res. Lett., 51, e2024GL111775, doi:10.1029/2024GL111775, 2024-10. [(1.69MB)] | |
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| 293. | Hou, Zengqian*, Jizhong Liu*, Yigang Xu, Fuchuan Pang*, Yuming Wang*, Liping Qin, Yang Liu*, Yu-Yan Sara Zhao, Guangfei Wei, Mengjiao Xu, Kun Jiang, Chuanpeng Hao, Shichao Ji, Renzhi Zhu, Bingkun Yu, Jia Liu, Zhenfeng Sheng, Juntao Wang, Chaolin Zhang, and Yiliang Li, The Search for Life Signatures on Mars by the Tianwen-3 Mars Sample Return Mission, Natl. Sci. Rev., 11, nwae313, doi:10.1093/nsr/nwae313, 2024-10. [(779.9KB)] | |
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| 292. | Liu, Jiajia*, Chunyu Ji, Yimin Wang, Szabolcs Soós, Ye Jiang, Robertus Erdélyi, M. B. Korsós, and Yuming Wang, Improving the Automated Coronal Jet Identification with U-NET, Astrophys. J., 972, 187(8pp), doi: 10.3847/1538-4357/ad66be, 2024-09. [(867.4KB)] | |
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| 291. | Cheng, Long*, Yuming Wang*, Robert Lillis, Benoit Langlais, Tielong Zhang, Jasper Halekas, David L. Mitchell, Jared Espley, and Shannon Curry, Two-spacecraft Observations of Asymmetric Martian Bow Shock: Conjunctions of Tianwen-1 and MAVEN, J. Geophys. Res. - Space Phys., 129, e2024JA033185, doi:10.1029/2024JA033185, 2024-09. [(5.09MB)] | |
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| 290. | Zhong, Zhihui, Chenglong Shen*, Yutian Chi*, Dongwei Mao, Bin Miao, Zhiyi Fu, Junyan Liu, Beatriz Sanchez-Cano, Daniel Heyner, and Yuming Wang, Prediction for Arrival Time and Parameters of Corotation Interaction Regions using Earth-Mars Correlated Events from Tianwen-1, MAVEN and Wind Observations, Astrophys. J., 965, 114(10pp), doi:10.3847/1538-4357/ad2fab, 2024-04. [(966.7KB)] | |
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| 289. | Song, Anchuan, Quanhao Zhang*, Yuming Wang, Rui Liu, Jie Jiang, Xiaolei Li, Jiajia Liu, Shaoyu Lv, and Ruobing Zheng, Solar cycle variation in the properties of photospheric magnetic concentrations, Astron. & Astrophys., 682, A87, doi:10.1051/0004-6361/202346898, 2024-02. [(22.59MB)] | |
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| 288. | Lyu, Shaoyu, Yuming Wang*, Xiaolei Li, Quanhao Zhang, and Jiajia Liu, Inferring the solar wind velocity in the outer corona based on multi-view observations of small-scale transients by STEREO/COR2, Astrophys. J., 962, 170(12pp), doi:10.3847/1538-4357/ad1dd5, 2024-02. [(5.75MB)] | |
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| 287. | Wu, Zhiyong, Zhenpeng Su*, Huinan Zheng, Yuming Wang, Yoshizumi Miyoshi, Iku Shinohara, Ayako Matsuoka, Yoshiya Kasahara, Fuminori Tsuchiya, Atsushi Kumamoto, Shoya Matsuda, Yasumasa Kasaba, Mariko Teramoto, and Tomoaki Hori, Long Lifetime Hiss Rays in the Disturbed Plasmasphere, Geophys. Res. Lett., 51, e2023GL107825, doi:10.1029/2023GL107825, 2024-02. [(1.34MB)] | |
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| 286. | Wang, Guoqiang, Sudong Xiao, Mingyu Wu, Yangdong Zhao, Song Jiang, Zonghao Pan, Xinjun Hao, Yiren Li, Kai Liu, Yutian Chi, Zhuxuan Zou, Manming Chen, Zhenpeng Su, Chenglong Shen, Jingnan Guo, Long Cheng, Zhiyong Wu, Mengjiao Xu, Yuming Wang*, and Tielong Zhang*, Calibration of the zero offset of the Fluxgate Magnetometer on board the Tianwen-1 orbiter in the Martian Magnetosheath, J. Geophys. Res. - Space Phys., 129, e2023JA031757, doi:10.1029/2023JA031757, 2024-01. [(850.4KB)] | |
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| 285. | Fu, Zhiyi, Zhenpeng Su*, Bin Miao, Zhiyong Wu, Yiren Li, Kai Liu, Xu Shan*, and Yuming Wang, A substorm-dependent negative limit of non-eclipse surface charging of a Chinese geosynchronous satellite, Space Weather, 22, e2023SW003780, doi:10.1029/2023SW003780, 2024-01. [(1.86MB)] | |
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| 284. | Cheng, Sanwei, Zhenpeng Su*, Zhiyong Wu, and Yuming Wang, Inferring whistler-mode chorus wave source regions in the Martian mini-magnetospheres, Geophys. Res. Lett., 51, e2023GL106695, doi:10.1029/2023GL106695, 2024-01. [(5.12MB)] | |
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| 2023 Top |
| 283. | Khuntia, Soumyaranjan*, Wageesh Mishra*, Sudheer K Mishra, Yuming Wang*, Jie Zhang, and Shaoyu Lyu, Unraveling the Thermodynamic Enigma between a Fast and Slow Coronal Mass Ejections, Astrophys. J., 958, 92(17pp), doi:10.3847/1538-4357/ad00ba, 2023-11. [(1.74MB)] | |
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| 282. | Zhang, Zhiyong, Chenglong Shen*, Yutian Chi*, Dongwei Mao, Junyan Liu, MengJiao Xu, Zhihui Zhong, Can Wang, and Yuming Wang, Comparison of I-ICMEs and M-ICMEs Fittings and In Situ Observation Parameters for Solar Cycles 23 and 24 and Their Influence on Geoeffectiveness, Sol. Phys., 298, 138, doi:10.1007/s11207-023-02225-3, 2023-11. [(2.97MB)] | |
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| 281. | Luo, Pengwei, Xiaoping Zhang*, Renrui Liu, Mingjie Zhang, Cunhui Li*, Yi Xu, Roberto Bugiolacchi, Baocheng Hua, Haiyan Zhang, Liansheng Li, Jilin You, Yanyan Xu, Lei Lei, Xin Zou, Qingfei Fu, Yi Wang, Xiao Liang, Jianhong Zhuang, Li Wang*, Yuming Wang, Weidong Wang, Linping Feng, Haiwen Liu, and Tao Li, Plume effects on Martian surface: Revealing evolution characteristics of plume-surface interaction at Tianwen-1 landing site, Engineering Geology, 325, 107278, doi:10.1016/j.enggeo.2023.107278, 2023-09. [(16.03MB)] | |
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| 280. | Zou, Zhuxuan, Yuming Wang*, Tielong Zhang, Guoqiang Wang, Sudong Xiao, Zonghao Pan, Zhoubin Zhang, Wei Yan, Yang Du, Yutian Chi, Long Cheng, Zhiyong Wu, Xinjun Hao, Yiren Li, Kai Liu, Manming Chen, Zhenpeng Su, Chenglong Shen, Mengjiao Xu, and Jingnan Guo, In-flight Calibration of the Magnetometer on the Mars Orbiter of Tianwen-1, Sci. China Tech. Sci., 66, 2396-2405, doi:10.1007/s11431-023-2401-2, 2023-08. [(2.41MB)] | |
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| 279. | Guo, Jingnan*, Xiaolei Li, Jian Zhang, Mikhail I. Dobynde, Yuming Wang, Zigong Xu, Thomas Berger, Jordanka Semkova, Robert F. Wimmer-Schweingruber, Donald M. Hassler, Cary Zeitlin, Bent Ehresmann, Daniel Matthia, and Bin Zhuang, The first ground level enhancement seen on three planetary surfaces: Earth, Moon and Mars, Geophys. Res. Lett., 50, e2023GL103069, doi:10.1029/2023GL103069, 2023-08. [ (4.34MB), (3.17MB)] | |
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| 278. | Mishra, Wageesh*, Yuming Wang*, Shaoyu Lyu, and Soumyaranjan Khuntia, Erratum: “Modeling the Thermodynamic Evolution of Coronal Mass Ejections Using Their Kinematics” (2018, ApJ, 865, 50), Astrophys. J., 952, 173(4pp), doi:10.3847/1538-4357/ace691, 2023-08. [(368.3KB)] | |
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| 277. | Cheng, Long, Robert Lillis*, Yuming Wang*, Anna Mittelholz, Shaosui Xu, David L. Mitchell, Catherine Johnson, Zhenpeng Su, Jasper S. Halekas, Benoit Langlais, Tielong Zhang, Guoqiang Wang, Sudong Xiao, Zhuxuan Zou, Zhiyong Wu, Yutian Chi, Zonghao Pan, Kai Liu, Xinjun Hao, Yiren Li, Manming Chen, Jared Espley, Frank Eparvier, and Shannon Curry, Martian bow shock oscillations driven by solar wind variations: simultaneous observations from Tianwen-1 and MAVEN, Geophys. Res. Lett., 50, e2023GL104769, doi:10.1029/2023GL104769, 2023-08. [(2.77MB)] | |
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| 276. | Chi, Yutian, Chenglong Shen, Long Cheng, Bingkun Yu, Bin Miao, Yuming Wang, Tielong Zhang, Zhuxuan Zou, Mengjiao Xu, Zonghao Pan, Jingnan Guo, Dongwei Mao, Zhihui Zhong, Zhiyong Zhang, Junyan Liu, Can Wang, Guoqiang Wang, Sudong Xiao, Kai Liu, Xinjun Hao, Yiren Li, and Manming Chen, Interplanetary Coronal Mass Ejections and Stream Interaction Regions Observed by Tianwen-1 and MAVEN at Mars, Astrophys. J. Supp., 267, 3(10pp), doi:10.3847/1538-4365/acd191, 2023-07. [(1.66MB)] | |
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| 275. | Chi, Yutian, Chenglong Shen*, Junyan Liu, Zhihui Zhong, Mathew Owens, Christopher Scott, Luke Barnard, Bingkun Yu, Daniel Heyner, Hans-Ulrich Auster, Ingo Richter, Yuming Wang, Tielong Zhang, Jingnan Guo, Beatriz Sanchez-Cano, Zonghao Pan, Zhuxuan Zou, Mengjiao Xu, Long Cheng, Zhenpeng Su, Dongwei Mao, Zhiyong Zhang, Can Wang, Zhiyong Wu, Guoqiang Wang, Sudong Xiao, Kai Liu, Xinjun Hao, Yiren Li, Manming Chen, and Mike Lockwood, The Dynamic Evolution of Multipoint Interplanetary Coronal Mass Ejections Observed with BepiColombo, Tianwen-1 and MAVEN, Astrophys. J. Lett., 951, L14(10pp), doi:10.3847/2041-8213/acd7e7, 2023-07. [(1.4MB)] | |
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| 274. | Wu, Zhiyong, Zhenpeng Su*, Huinan Zheng, and Yuming Wang, Filtering of Magnetosonic Waves by Mesoscale Plasmaspheric Density Interfaces, Geophys. Res. Lett., 50, e2023GL103590, doi:10.1029/2023GL103590, 2023-06. [(16.18MB)] | |
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| 273. | Zheng, Ruobing, Yuming Wang*, Xiaolei Li, Chuanbing Wang, and Xianzhe Jia, Statistical study on the jovian decametric radio emissions based on multiple-view observations from remote radio instruments, Astron. & Astrophys., 673, A106, doi:10.1051/0004-6361/202244121, 2023-05. [(17.53MB)] | |
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| 272. | Gou, Tingyu*, Rui Liu*, Astrid M. Veronig, Bin Zhuang, Ting Li, Wensi Wang, Mengjiao Xu, and Yuming Wang, Complete replacement of magnetic flux in a flux rope during a coronal mass ejection, Nat. Astron., 7, 815-824, doi:10.1038/s41550-023-01966-2, 2023-05. [(6.33MB)] | |
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| 271. | Zhou, Hao, Xueke Wang, Siqi Liu, Lei Cheng, Kai Liu, Zonghao Pan, Yiren Li, Xinjun Hao, Dong sheng, and Yuming Wang, Signal-processing electronics for stable and sensitive weak-field atomic vector magnetometers, Rev. Sci. Instr., 94, 054701, doi:10.1063/5.0150256, 2023-05. [(6.06MB)] | |
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| 270. | Li, Xiaolei, Yuming Wang*, Fang Shen, Yi Yang, Quanhao Zhang, and Shaoyu Lyu, Reconstructing Synoptic Maps of Solar Wind Radial Velocity between 20 and 60 Solar Radii Based on STEREO/HI1 Images, Astrophys. J., 949, 58(11pp), doi:10.3847/1538-4357/acc6c8, 2023-05. [(3.04MB)] | |
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| 269. | Liu, Jiajia*, Anchuan Song, David B.Jess, JieZhang, Mihalis Mathioudakis, Szabolcs Soós, Francis P.Keenan, Yuming Wang*, and Robertus Erdélyi*, Power-law Distribution of Solar Cycle-modulated Coronal Jets, Astrophys. J. Supp., 266, 17(15pp), doi:10.3847/1538-4365/acc85a, 2023-05. [(7.66MB)] | |
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| 268. | Wang, Rongsheng*, Xiancai Yu, Yuming Wang, Quanming Lu, and San Lu, Observation of the Hall magnetic reconnection as close as 56 solar radii to the Sun, Astrophys. J., 947, 78, doi:10.3847/1538-4357/acbdf6, 2023-04. [(3.58MB)] | |
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| 267. | Lyu, Shaoyu*, Yuming Wang*, Xiaolei Li, and Quanhao Zhang, Optimal stereoscopic angle for 3D reconstruction of synthetic small-scale coronal transients using the CORAR technique, Astron. & Astrophys., 672, A100, doi:10.1051/0004-6361/202243912, 2023-04. [(25.55MB)] | |
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| 266. | You, Jilin, Xiaoping Zhang*, Hsinchen Yu, Haiyan Zhang, Cunhui Li*, Roberto Bugiolacchi, Yi Xu, Yi Wang, Pengwei Luo, Liping Chen*, Baogui Zhang, Yingqiao Xu, Yongfu Hu, Tong Wang, Yuming Wang, Qingfei Fu, Yupeng Gao, Weidong Wang, Qijun Zhi, Linping Feng, Haiwen Liu, Yifei Cui, and Jiayan Nie, Unveiling the mechanics of lunar regolith erosion through analysis of CE-4 and CE-5 landing images and fluid simulation, Acta Astronautica, 208, 343, doi:10.1016/j.actaastro.2023.04.024, 2023-04. [(4.68MB)] | |
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| 265. | Su, Zhenpeng*, Yuming Wang*, Tielong Zhang, Zhiyong Wu, Long Cheng, Zhuxuan Zou, Chenglong Shen, Jingnan Guo, Sudong Xiao, Guoqiang Wang, Zonghao Pan, Kai Liu, Xinjun Hao, Yiren Li, Manming Chen, Yutian Chi, and Mengjiao Xu, Unusual Martian Foreshock Waves Triggered by a Solar Wind Stream Interaction Region, Astrophys. J. Lett., 947, L33, doi:10.3847/2041-8213/accb9f, 2023-04. [(2.92MB)] | |
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| 264. | SHAN Xu*, MIAO Bin, CAO Zhe, SUN ZhenYu, LI YiRen, LIU Kai, GUO XingYu, QU SanBiao, SU ZhenPeng, SHEN ChengLong, PAN ZongHao, LI Xin, HAO XinJun, YANG XiaoPing, TIAN Chao, JIANG Yu, LIU ShuBin, AN Qi, CHEN XiangJun, and WANG YuMing*, First results of the low energy ion spectrometer onboard a Chinese geosynchronous satellite, Science China Technological Sciences, 66, doi:10.1007/s11431-022-2143-6, 2023-03. [(1.76MB)] | |
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| 263. | Wang, Yuming*, Tielong Zhang, Guoqiang Wang, Sudong Xiao, Zuxuan Zou, Long Cheng, Zonghao Pan, Kai Liu, Xinjun Hao, Yiren Li, Manming Chen, Zhoubin Zhang, Wei Yan, Zhenpeng Su, Zhiyong Wu, Chenglong Shen, Yutian Chi, Mengjiao Xu, Jingnan Guo, and Yang Du, The Mars Orbiter Magnetometer of Tianwen-1: In-flight Performance and First Science Results, Earth and Planetary Physics, 7, 1-13, doi:10.26464/epp2023028 (https://arxiv.org/abs/2301.00677), 2023-03. [(19.05MB)] | |
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| 262. | SHAN Xu*, MIAO Bin, CAO Zhe, SUN ZhenYu, LI YiRen, LIU Kai, GUO XingYu, QU SanBiao, SU ZhenPeng, SHEN ChengLong, PAN ZongHao, LI Xin, HAO XinJun, YANG XiaoPing, TIAN Chao, JIANG Yu, LIU ShuBin, AN Qi, CHEN XiangJun, and WANG YuMing, A low-energy ion spectrometer with large field of view and wide energy range onboard a Chinese GEO satellite, Open Astronomy, 32, doi:10.1515/astro-2022-0210, 2023-02. [(6.6MB)] | |
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| 261. | Wang, Wensi*, Jiong Qiu, Rui Liu, Chunming Zhu, Kai E Yang, Qiang Hu, and Yuming Wang, Investigating pre-eruptive magnetic properties at the footprints of erupting magnetic flux ropes, Astrophys. J., 943, 80, doi:10.3847/1538-4357/aca6e1, 2023-02. [(5.11MB)] | |
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| 260. | Zhou, Zhenjun, Chaowei Jiang Hongqiang Song, Yuming Wang, Yongqiang Hao, and Jun Cui, Quantification of the Writhe Number Evolution of Solar Filament Axes, Astrophys. J., 944, 175, doi:10.3847/1538-4357/acb6f8, 2023-02. [(1.46MB)] | |
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| 259. | Zhou, Zhenjun*, Chaowei Jiang*, Xiaoyu Yu, Yuming Wang, Yong-Qiang Hao, and Jun Cui, The Mechanism of Magnetic Flux Rope Rotation During Solar Eruption, Front. Phys., 11, doi:10.3389/fphy.2023.1119637, 2023-02. [(1.32MB)] | |
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| 258. | Wang, Yuming* and et al., Solar Ring Mission: Building a Panorama of the Sun and Inner-heliosphere, Adv. Space Res., 71, 1146-1164, doi: 10.1016/j.asr.2022.10.045, 2023-01. [(1.55MB)] | |
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| 257. | Zhang, Quanhao*, Xin Cheng, Rui Liu, Anchuan Song, Xiaolei Li, and Yuming Wang, Influence of magnetic reconnection on the eruptive catastrophes of coronal magnetic flux ropes, Frontiers in Astronomy and Space Sciences, 9, doi:10.3389/fspas.2022.1084678, 2023-01. [(47.68MB)] | |
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| 2022 Top |
| 256. | Cheng, Long* and Yuming Wang*, The variation of the solar wind correlation scale and Taylor scale upstream of Mars observed by MAVEN, Astrophys. J., 941, 37(7pp), doi:10.3847/1538-4357/aca0f2, 2022-12. [(1.37MB)] | Abstract. The correlation scale and Taylor scale, which characterize the turbulence and dissipation levels, of the solar wind upstream of Mars are determined using the Mars atmosphere and volatile evolution magnetic field data from 2015 to 2020, which covers half of a solar cycle from the solar maximum to the solar minimum. Our analysis suggests that the correlation scale varies between 10 and 20 hr and the Taylor scale between 0.3 and 1 s. Applying the frozen-in flow approximation, we convert the two temporal scales to the two spatial scales, which are about (1.5–3.0) × 10 7 km and 150–500 km, respectively. We further compare the correlation scale and Taylor scale to the sunspot number (SSN) to study the impacts of solar activity. The highest correlation coefficient between the correlation scale and the SSN is 0.78, where the two data sets are shifted by 16 months with the correlation scale behind the SSN. For the Taylor scale, the highest correlation coefficient is 0.52 with the time lag of 17 months. We also analyze the effective magnetic Reynolds number that is the square of the ratio of the two scales. It is more than 3 × 10 9 , suggesting the good assumption of the frozen-in flow. However, its correlation with the SSN is weak.
We thank the public data of MAVEN MAG and SWIA provided by NASA Planetary Data System. We acknowledge the sunspot number data from the WDC-SILSO, Royal Observatory of Belgium, Brussels (https://www.sidc.be/silso/datafiles). This research is supported by the Strategic Priority Program of CAS (XDB41000000) and the grants from NSFC (42130204 and 42188101). Y.W. is particularly grateful for the support of the Tencent Foundation. |
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| 255. | Wu, Zhiyong, Zhenpeng Su*, Zhaoguo He*, Huinan Zheng, and Yuming Wang, Magnetosonic Waves Above the Lower Hybrid Frequency in Cyclotron Resonance With the Van Allen Radiation Belt Electrons, Geophys. Res. Lett., 49, e2022GL100971, doi: 10.1029/2022GL100971, 2022-11. [(4.02MB)] | |
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| 254. | Dang, Tong, Xiaolei Li, Bingxian Luo, Ruoxi Li, Dexin Ren, Xuetao Chen, Binzheng Zhang, Jiuhou Lei*, and Yuming Wang*, Unveiling the space weather during the Starlink satellites destruction event on 4 February 2022, Space Weather, 20, e2022SW003152, doi:10.1029/2022SW003152, 2022-08. [(4.3MB), (1.87MB)] | |
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| 253. | Liu, Lijuan, Zhenjun Zhou, Yuming Wang, Xudong Sun, and Guoqiang Wang, On the nature of photospheric horizontal magnetic field increase in major solar flares, Astrophys. J. Lett., 934, L33(10pp), doi:10.3847/2041-8213/ac83bf, 2022-08. [(2.14MB)] | |
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| 252. | Chi, Yutian, Chenglong Shen*, Christopher Scott, Mengjiao Xu, Mathew Owens, Yuming Wang, and Mike Lockwood, Predictive Capabilities of Corotating Interaction Regions using STEREO and Wind In-situ Observations, Space Weather, 20, e2022SW003112, doi:10.1029/2022SW003112, 2022-08. [(1.85MB)] | |
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| 251. | Wu, Zhiyong, Zhenpeng Su, Jerry Goldstein, Nigang Liu, Zhaoguo He, Huinan Zheng, and Yuming Wang, Nightside Plasmaspheric Plume-To-Core Migration of Whistler-Mode Hiss Waves, Geophys. Res. Lett., 49, e2022GL100306, doi:10.1029/2022GL100306, 2022-08. [(5.51MB)] | |
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| 250. | Fu, Shuai, Zheyi Ding, Yongjie Zhang, Xiaoping Zhang, Cunhui Li, Gang Li, Shuwen Tang, Haiyan Zhang, Yi Xu, Yuming Wang, Jingnan Guo, Lingling Zhao, Yi Wang, Xiangyu Hu, Pengwei Luo, Zhiyu Sun, Yuhong Yu, and Lianghai Xie, First report of a solar energetic particle event observed by China's Tianwen-1 mission in transit to Mars, Astrophys. J. Lett., 934, L15(8pp), doi:10.3847/2041-8213/ac80f5, 2022-07. [(1.2MB)] | |
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| 249. | Zhao, Ake*, Yuming Wang, Hengqiang Feng, Long Cheng, Xiaolei Li, Qiangwei Cai, Hongbo Li, and Guoqing Zhao, The Radial Evolution of Magnetic Clouds From Helios to Ulysses, Astrophys. J., 931, 55(10pp), doi:10.3847/1538-4357/ac69c8, 2022-05. [(468.4KB)] | |
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| 248. | Xu, Mengjiao, Chenglong Shen, Can Wang, Yutian Chi, Zhihui Zhong, and Yuming Wang, Multipoint Analysis of the Interaction between a Shock and an ICME-like Structure around 2011 March 22, Astrophys. J. Lett., 930, L11, doi:10.3847/2041-8213/ac6879, 2022-05. [(1.06MB)] | |
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| 247. | Chen, Manming, Zonghao Pan*, Tielong Zhang*, Xinjun Hao, Yiren Li, Kai Liu, Xin Li, Yuming Wang, Chenglong Shen, Hong Chen, Zhongwang Wang, and Xiu Qiang, Deployable boom for Mars Orbiter Magnetometer onboard Tianwen-1, J. Univ. of Sci. & Tech. of China, 52, 7, doi:10.52396/JUSTC-2022-0001, 2022-05. | |
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| 246. | Wang, Yuming*, Jingnan Guo*, Gang Li, Elias Roussos, and Junwei Zhao, Variation in Cosmic-Ray Intensity Lags Sunspot Number: Implications of Late Opening of Solar Magnetic Field, Astrophys. J., 928, 157(12pp), doi:10.3847/1538-4357/ac5896, 2022-04. [(8.11MB), (2.06MB)] | |
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| 245. | Cheng, Long, Yuming Wang*, and Xiaolei Li, Using Single-View Observations of Cometary Plasma Tails to Infer Solar Wind Speed, Astrophys. J., 928, 121(10pp), doi:10.3847/1538-4357/ac5410, 2022-04. [(7.73MB)] | |
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| 244. | Chen, Zewen, Zhenpeng Su, Zhaoguo He, Zhiyong Wu, Guyue Dai, Bin Wang, Ying Xiong, Huinan Zheng, Jun Cui, and Yuming Wang, A Rapid Localized Deceleration of Earth's Radiation Belt Relativistic Electrons Driven by Storm Proton Injection, Geophys. Res. Lett., 49, doi:10.1029/2022GL098810, 2022-04. | |
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| 243. | Shen, Fang*, Chenglong Shen*, Mengjiao Xu, Yousheng Liu, Xueshang Feng, and Yuming Wang, Propagation characteristics of coronal mass ejections (CMEs) in the corona and interplanetary space, Reviews of Modern Plasma Physics, 6, 8, doi:10.1007/s41614-022-00069-1, 2022-04. [(12.8MB)] | |
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| 242. | Li, Xiaolei, Yuming Wang*, Jingnan Guo, and Shaoyu Lyu, Solar energetic particles produced during two fast coronal mass ejections, Astrophys. J. Lett., 928, L6(8pp), doi:10.3847/2041-8213/ac5b72, 2022-03. [(1.15MB)] | |
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| 241. | Zhou, Zhenjun, Chaowei Jiang, Rui Liu, Yuming Wang, Lijuan Liu, and Jun Cui, The Rotation of Magnetic Flux Rope Formed during a Solar Eruption, Astrophys. J. Lett., 927, L14, doi:10.3847/2041-8213/ac5740, 2022-03. | |
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| 240. | Jin, Yuyue, Nigang Liu*, Zhenpeng Su*, Huinan Zheng, Yuming Wang, and Shui Wang, Immediate Impact of Solar Wind Dynamic Pressure Pulses on Whistler-Mode Chorus Waves in the Inner Magnetosphere, Geophys. Res. Lett., 49, doi:10.1029/2022GL097941, 2022-03. | |
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| 239. | Zhou, Zhenjun, Rui Liu, Jianqing Sun, Jie Zhang, Mingde Ding, Xin Cheng, Yuming Wang, Xiaoyu Yu, Lijuan Liu, and Jun Cui, Resolving Two Distinct Thermal X-ray Components in A compound Solar Flare, Astrophys. J., 925, 132(8pp), doi:10.3847/1538-4357/ac3bbe, 2022-02. [(1.34MB)] | |
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| 238. | Zhang, Jian, Jingnan Guo*, Mikhail I. Dobynde, Yuming Wang, and Robert F. Wimmer-Schweingruber, From the top of Martian Olympus to Deep Craters and Beneath: Mars Radiation Environment under Different Atmospheric and Regolith Depths, J. Geophys. Res. - Planets, 127, doi:10.1029/2021JE007157, 2022-02. [(3.58MB)] | |
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| 237. | Wang, Yuming*, Ruobing Zheng, Xianzhe Jia, Chuanbing Wang, Shui Wang, and V. Krupar, Reply to Comment by Lamy et al. on “Locating the source field lines of Jovian decametric radio emissions”, Earth & Planet. Phys., 6, 13-17, doi:10.26464/epp2022019, 2022-01. [(530.5KB)] | |
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| 236. | Erdelyi, Robertus and et al., The Solar Activity Monitor Network - SAMNet, J. Space Weather and Space Climate, 12, 2, doi:10.1051/swsc/2021025, 2022-01. | |
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| 2021 Top |
| 235. | Zhang, Quanhao, Rui, Liu, Yuming, Wang, Xiaolei, Li, and Shaoyu, Lyu, Confined and eruptive catastrophes of solar magnetic flux ropes caused by mass loading and unloading, Astrophys. J., 921, 172, doi:10.3847/1538-4357/ac1fef, 2021-11. [(369.2KB)] | |
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| 234. | Shen, Chenglong*, Yutian Chi, Mengjiao Xu, and Yuming Wang, Origin of Extremely Intense South Component of Magnetic Field (B_s) in ICMEs, Frontiers in Physics, 9, 762488, doi:10.3389/fphy.2021.762488, 2021-11. [(6.13MB)] | |
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| 233. | Zhang, Jie*, Manuela Temmer, Nat Gopalswamy, Olga Malandraki, Nariaki V. Nitta, Spiros Patsourakos, Fang Shen, Bojan Vrsnak, Yuming Wang, David Webb, Mihir I. Desai, Karin Dissauer, Nina Dresing, Mateja Dumbovic, Xueshang Feng, Stephan G. Heinemann, Monica Laurenza, Noe Lugaz, and Bin Zhuang, Earth-affecting Solar Transients: A Review of Progresses in Solar Cycle 24, Progress in Earth and Planetary Science, 8, 56, doi:10.1186/s40645-021-00426-7, 2021-10. [(13.03MB)] | |
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| 232. | Liu, Rui* and Yuming Wang, Investigation on the Spatiotemporal Structures of Supra-Arcade Spikes, Astron. & Astrophys., 653, A51, 2021-09. [(3.24MB)] | |
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| 231. | Guo, Jingnan, Cary Zeitlin, Robert F. Wimmer-Schweingruber, Donald M. Hassler, Bent Ehresmann, Scot Rafkin, Johan L. Freiherr von Forstner, Salman Khaksarighiri, Weihao Liu, and Yuming Wang, Radiation Environment for future Human Exploration on the surface of Mars: The Current Understanding based on MSL/RAD Dose Measurements, The Astronomy and Astrophysics Review, 29, 8(81pp), 2021-09. [(15.06MB)] | |
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| 230. | Zhong, Zhihui, Chenglong Shen*, Dongwei Mao, Yutian Chi, Mengjiao Xu, Jiayi Liu, and Yuming Wang, Three-Dimensional Parameters of the Earth-Impacting CMEs based on GCS Model, Universe, 7, 361, 2021-09. [(2.43MB)] | |
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| 229. | Chi, Yutian, Christopher Scott*, Chenglong Shen*, Luke Barnard, Mathew Owens, Mengjiao Xu, Jie Zhang, Shannon Jones, Zhihui Zhong, Bingkun Yu, Matthew Lang, Yuming Wang, and Mike Lockwood, Modelling the observed distortion of multiple (ghost) CME fronts in STEREO Heliospheric imagers, Astrophys. J. Lett., 917, L16(8pp), 2021-08. [(6.46MB)] | |
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| 228. | 周茹芸, 汪毓明*, 宿英娜, 毕少兰, 刘睿, and 季海生*, 模拟利用双视角改正太阳矢量磁场观测中的180度不确定性, 天文学报, 62, 41, 2021-07. [(6.23MB)] | |
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| 227. | Xiaolei Li*, Yuming Wang*, Jingnan Guo, Rui Liu, and Bin Zhuang, Radial velocity map of solar wind transients in the field of view of STEREO/HI1 on 3 and 4 April 2010, Astron. & Astrophys., 649, A58, doi:10.1051/0004-6361/202039766, 2021-05. [(14.94MB)] | |
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| 226. | Cheng, Zhixun, Yuming Wang*, and Rui Liu, Correcting Doppler Shifts in He II 30.38 nm Line by Using the EVE and AIA data from Solar Dynamics Observatory, Astrophys. J., 911, 36(7pp), 2021-04. [(1.27MB)] | |
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| 225. | Liu, Lijuan, Jiajia Liu, Jun Chen, Yuming Wang, Guoqiang Wang, Zhenjun Zhou, and Jun Cui, The configuration and failed eruption of a complex magnetic flux rope above a δ sunspot region, Astron. & Astrophys., 648, A106, 2021-04. [(5.07MB)] | |
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| 224. | Lyu, Shaoyu, Yuming Wang*, Xiaolei Li, Jingnan Guo, Chuanbing Wang, and Quanhao Zhang, Three-dimensional Reconstruction of Coronal Mass Ejections by the Correlation-aided Reconstruction Technique through Different Stereoscopic Angles of the Solar Terrestrial Relations Observatory Twin Spacecraft, Astrophys. J., 909, 182(11pp), doi:10.3847/1538-4357/abd9c9, 2021-03. [(2.64MB)] | |
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| 223. | Wang, Can, Mengjiao Xu, Chenglong Shen, Yutian Chi, and Yuming Wang, Interplanetary shock candidates observed at Venus's orbit, Astrophys. J., 912, 85(12pp), 2021-03. [(1.47MB)] | |
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| 222. | Pan, Hanya, Rui Liu, Tingyu Gou, Bernhard Kliem, Yingna Su, Jun Chen, and Yuming Wang, Pre-eruption Splitting of the Double-Decker Structure in a Solar Filament, Astrophys. J., 909, 32(12pp), 2021-03. [(3.92MB)] | |
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| 221. | Liu, Lijuan, Yuming Wang, Zhenjun Zhou, and Jun Cui, The Source Locations of Major Flares and CMEs in Emerging Active Regions, Astrophys. J., 909, 142(23pp), 2021-03. [(13.04MB)] | |
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| 220. | Wu, Zhiyong, Zhenpeng Su*, Nigang Liu*, Zhonglei Gao, Huinan Zheng, Yuming Wang, and Shui Wang, Off-Equatorial Source of Magnetosonic Waves Extending Above the Lower Hybrid Resonance Frequency in the Inner Magnetosphere, Geophys. Res. Lett., 48, e2020GL091830, dio:10.1029/2020GL091830, 2021-03. [(3.52MB)] | |
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| 219. | Liu, Jiajia#, Yimin Wang#, Xin Huang, Marianna B. Korsós, Ye Jiang, Yuming Wang, and Robert Erdélyi*, Reliability of AI-generated magnetograms from only EUV images, Nature Astronomy, , doi:10.1038/s41550-019-0711-5, 2021-02. [(1.08MB)] | |
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| 218. | Wang, Yamin, Xin Chen, Pengcheng Wang, Chengbo Qiu, Yuming Wang, and Yonghe Zhang, Concept of the Solar Ring Mission: Preliminary Design and Mission Profile, Science China Technological Sciences, 64, 131-138, doi:10.1007/s11431-020-1612-y, 2021-01. [(2.17MB)] | |
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| 217. | Zhang, Quanhao, Rui Liu, Yuming Wang, Zhenjun Zhou, Bin Zhuang, and Xiaolei Li, How flux feeding causes eruptions of solar magnetic flux ropes with the hyperbolic flux tube configuration?, Astron. & Astrophys., 647, A171, 2021-01. [(1.91MB)] | |
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| 2020 Top |
| 216. | Xu, Mengjiao, Chenglong Shen*, Qiang Hu, Yuming Wang, and Yutian Chi, Whether Small Flux Ropes and Magnetic Clouds Have the Same Origin: A Statistical Study of Small Flux Ropes in Different Types of Solar Wind, Astrophys. J., 904, 122(10pp), doi:10.3847/1538-4357/abbe21, 2020-11. [(4.66MB)] | |
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| 215. | Joshi, Reetika, Yuming Wang, Ramesh Chandra, Quanhao Zhang, Lijuan Liu, and Xiaolei Li, Cause and Kinematics of a Jetlike CME, Astrophys. J., 901, 94(8pp), 2020-10. [(1.66MB)] | |
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| 214. | Xu, Zigong, Jingnan Guo, Robert F. Wimmer-Schweingruber, Johan L. Freiherr von Forstner, Yuming Wang, Nina Dresing, Henning Lohf, Shenyi Zhang, Bernd Heber, and Mei Yang, First Solar Energetic Particles Measured on the Lunar Far-side, Astrophys. J. Lett., 902, L30(8pp), 2020-10. [(3.08MB)] | |
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| 213. | Su, Zhenpeng, Nigang Liu, Zhonglei Gao, Bin Wang, Huinan Zheng, Yuming Wang, and Shui Wang, Rapid Landau Heating of Martian Topside Ionospheric Electrons by Large-Amplitude Magnetosonic Waves, Geophys. Res. Lett., 47, e2020GL090190, doi:10.1029/2020GL090190, 2020-10. [(4.67MB)] | |
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| 212. | Lyu, Shaoyu, Xiaolei Li*, and Yuming Wang*, Optimal Stereoscopic Angle for Reconstructing Solar Wind Inhomogeneous Structures, Adv. Space Res., 66, 2251-2264, doi:10.1016/j.asr.2020.07.045, arXiv:2005.06838, 2020-09. [(2.79MB)] | |
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| 211. | He, Yuwei, Rui Liu, Lijuan Liu, Jun Chen, Wensi Wang, and Yuming Wang, Electric Currents through J-shaped and Non-J-shaped Flare Ribbons, Astrophys. J., 900, 38(11pp), 2020-09. [(1.23MB)] | |
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| 210. | Zhuang, Bin, Noe Lugaz, Tingyu Gou, Liuguan Ding, and Yuming Wang, The Role of Successive and Interacting CMEs in the Acceleration and Release of Solar Energetic Particles: Multi-viewpoint Observations, Astrophys. J., 901, 45(14pp), 2020-09. [(2.11MB)] | |
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| 209. | Wang, Zhongshan, Zhenpeng Su, Nigang Liu, Guyue Dai, Huinan Zheng, Yuming Wang, and Shui Wang, Suprathermal Electron Evolution Under the Competition Between Plasmaspheric Plume Hiss Wave Heating and Collisional Cooling, Geophys. Res. Lett., 47, e2020GL089649, 2020-09. [(6.5MB)] | |
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| 208. | Chi, Yutian, Christopher Scott, Chenglong Shen, Mathew Owens, Matthew Lang, Mengjiao Xu, Zhihui Zhong, Jie Zhang, Yuming Wang, and Mike Lockwood, Using "Ghost fronts" to predict the arrival time and speed of CME at Venus and Earth, Astrophys. J., 899, 143(14pp), 2020-08. [(6.73MB)] | |
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| 207. | Liu, Kai#, XinJun Hao#, YiRen Li#, TieLong Zhang*, ZongHao Pan, ManMing Chen, XiaoWen Hu, Xin Li, ChengLong Shen, and YuMing Wang*, Mars Orbiter Magnetometer of China’s First Mars Mission Tianwen-1, Earth & Planet. Phys., , doi:10.26464/epp2020058, 2020-08. [(372.4KB)] | |
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| 206. | Liu, Nigang, Zhenpeng Su*, Zhonglei Gao, Huinan Zheng, Yuming Wang, and ShuiWang, Can solar wind decompressive discontinuities suppress magnetospheric electromagnetic ion cyclotron waves associated with fresh proton injections?, Geophys. Res. Lett., 47, doi:10.1029/2020GL090296, 2020-08. [(4.81MB)] | |
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| 205. | Li, Xiaolei, Yuming Wang*, Rui Liu, Chenglong Shen, Quanhao Zhang, Shaoyu Lyu, Bin Zhuang, Fang Shen, Jiajia Liu, and Yutian Chi, Reconstructing solar wind inhomogeneous structures from stereoscopic observations in white-light: Solar wind transients in 3D, J. Geophys. Res. - Space Phys., 125, doi:10.1029/2019JA027513, 2020-07. [(7.29MB)] | |
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| 204. | Cheng, Long, Quanhao Zhang*, Yuming Wang*, Xiaolei Li, and Rui Liu, Using Stereoscopic Observations of Cometary Plasma Tails to Infer Solar Wind Speed, Astrophys. J., 897, 87(10pp), 2020-07. [(1.38MB)] | Abstract. Detection of the solar wind speed near the Sun is significant in understanding the heating and acceleration of the solar wind. Cometary plasma tails have long been used as natural probes for solar wind speed; previous solar wind speed estimates via plasma tails, however, were based on comet images from a single viewpoint, and the projection effect may influence the result. Using stereoscopic observations from STEREO and SOHO, we three-dimensionally reconstruct the plasma tails of three comets C/2012 S1 (ISON), C/2010 E6 and C/2011 W3 (Lovejoy) and infer the ambient solar wind speed. The first comet is located between 3.5 and 6 solar radii (Rs) away from the Sun at high latitudes; the estimated solar wind speed is about 300–500 km s-1. The second comet is located within 10 Rs and about 20 degrees away from the ecliptic; the estimated solar wind speed is about 200–320 km s-1. The third comet is also located at low latitudes but farther (>20 Rs) away from the Sun; the estimated solar wind speed is about 100-600 km s-1. For comets near the ecliptic, our results are close to those predicted by MHD models, whereas for the comet at high latitudes, the deviation between our estimate and the model results is notable. This consistency and difference could be used to constrain and improve solar wind models. We will seek opportunities to apply the method to comet 322P, whose tail may sweep Parker Solar Probe.
This research is supported by the Strategic Priority Program of CAS (XDB41000000 and XDA15017300), the grants from NSFC (Nos. 41804161, 41774178, and 41574165), and the fundamental research funds for the central universities. We thank the NASA’s STEREO mission team for their public data available on several websites, including the STEREO Science Center (SSC) and STEREO FTP server. We also acknowledge the general tools in the IDL Solar SoftWare (SSW) package contributed by the solar physics community. MHD simulations are run on the Community Coordinated Modeling Center (CCMC) website at NASA/GSFC. We appreciate all the modeling teams for providing their models at the CCMC. |
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| 203. | Gou, Tingyu, Astrid M. Veronig, Rui Liu, Bin Zhuang, Mateja Dumbovic, Tatiana Podladchikova, Hamish A. S. Reid, Manuela Temmer, Karin Dissauer, Bojan Vrsnak, and Yuming Wang, Solar Flare-CME Coupling Throughout Two Acceleration Phases of a Fast CME, Astrophys. J. Lett., 897, L36(9pp), 2020-07. [(3.2MB)] | |
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| 202. | Zhang, Quanhao, Yuming Wang, Rui Liu, Jie Zhang, Youqiu Hu, Wensi Wang, Bin Zhuang, and Xiaolei Li, Eruption of Solar Magnetic Flux Ropes Caused by Flux Feeding, Astrophys. J. Lett., 898, L12(8pp), 2020-07. [(799.5KB)] | |
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| 201. | Raghav, Anil*, Sandesh Gaikwad, Yuming Wang*, Zubair I. Shaikh, Wageesh Mishra, and Ake Zao, Study of flux rope characteristics at sub-astronomical-unit distances using the Helios 1 and 2 spacecraft, Mon. Not. R. Astron. Soc., 495, 1566-1576, doi:10.1093/mnras/staa1189, 2020-05. [(1.98MB)] | |
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| 200. | Wang, Yuming*, Haisheng Ji, Yamin Wang, Lidong Xia, Chenglong Shen, Jingnan Guo, Quanhao Zhang, Zhenghua Huang, Kai Liu, Xiaolei Li, Rui Liu, Jingxiu Wang, and Shui Wang, Concept of the Solar Ring Mission: An Overview, Science China Technological Sciences, 63, 1699-1713, doi:10.1007/s11431-020-1603-2, arXiv:2003.12728, 2020-05. [(11.13MB), (1.05MB), (2.9MB), (332KB),  (1.74MB), (4.04MB), (14.43MB), (2.34MB), (4.66MB)] | |
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| 199. | Zhou, Zhenjun, Rui Liu, Xing Cheng, Chaowei Jiang, Yuming Wang, Lijuan Liu, and Jun Cui, The Relationship between Chirality, Sense of Rotation, and Hemispheric Preference of Solar Eruptive Filaments, Astrophys. J., 891, 180(6pp), 2020-03. [(0.99MB)] | |
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| 198. | Chen, Jun, Rui Liu, Kai Liu, Arun Kumar Awasthi, Peijin Zhang, Yuming Wang, and Bernhard Kliem, Extreme-ultraviolet Late Phase of Solar Flares, Astrophys. J., 890, 158(10pp), 2020-02. [(3.71MB)] | |
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| 197. | Wang, Yuming*, Xianzhe Jia, Chuanbing Wang, Shui Wang, and V. Krupar, Locating the Source Field Lines of Jovian Decametric Radio Emissions, Earth and Planetary Physics, 4, 95-104, doi: 10.26464/epp2020015, 2020-02. [(5.75MB), (11.09MB), (3.33MB)] | |
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| 196. | Cui, Jun*, ZhaoJin Rong, Yong Wei, and YuMing Wang, Recent investigations of the near-Mars space environment by the planetary aeronomy and space physics community in China, Earth & Planet. Phys., 4, 1-3, doi:10.26464/epp2020001, 2020-02. [(158.9KB)] | |
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| 195. | Guo, Jingnan, Robert F. Wimmer-Schweingruber, Mateja Dumbovic, Bernd Heber, and Yuming Wang, A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence, Earth & Planet. Phys., 4, 1-11, doi:10.26464/epp2020007, 2020-01. | |
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| 194. | Mishra, Wageesh, Yuming Wang, Luca Teriaca, Jie Zhang, and Yutian Chi, Probing the thermodynamic state of a Coronal Mass Ejection (CME) up to 1 AU, Frontiers in Astronomy and Space Sciences, 7, doi:10.3389/fspas.2020.00001, 2020-01. | |
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| 193. | Liu, Nigang, Zhenpeng Su, Zhonglei Gao, Huinan Zheng, Yuming Wang, Shui Wang, Yoshizumi Miyoshi, Iku Shinohara, Yoshiya Kasahara, Fuminori Tsuchiya, Atsushi Kumamoto, Shoya Matsuda, Masafumi Shoji, Takefumi Mitani, Takeshi Takashima, Yoichi Kazama, Bo-Jhou Wang, Shiang-Yu Wang, Chae-Woo Jun, Tzu-Fang Chang, Sunny W. Y. Tam, Satoshi Kasahara, Shoichiro Yokota, Kunihiro Keika, Tomoaki Hori, and Ayako Matsuoka, Comprehensive Observations of Substorm-Enhanced Plasmaspheric Hiss Generation, Propagation, and Dissipation, Geophys. Res. Lett., 47, e2019GL086040, 2020-01. [(8.2MB)] | |
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| 2019 Top |
| 192. | Xu, Mengjiao, Chenglong Shen*, Yutian Chi, Yuming Wang, Qiang Hu, Gang Li, Zhihui Zhong, and Jiayi Liu, The Enhancement of the Energetic Particle Intensities in ICMEs, Astrophys. J., 885, 54(12pp), 2019-11. [(11.26MB)] | |
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| 191. | Zhao, Ake*, Yuming Wang*, Hengqiang Feng, Bin Zhuang, Xiaolei Li, Hongbo Li, and Hong Jia, The Relationship of Magnetic Twist and Plasma Motion in a Magnetic Cloud, Astrophys. J., 885, 122(5pp), 2019-11. [(404.8KB)] | |
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| 190. | Liu, Lijuan, Xin Cheng, Yuming Wang, and Zhenjun Zhou, Formation of a Magnetic Flux Rope in the early emergence phase of NOAA active region 12673, Astrophys. J., 884, 45(17pp), 2019-10. [(7.33MB)] | |
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| 189. | Xu, Mengjiao, Chenglong Shen, Yuming Wang, Bingxian Luo, and Yutian Chi, Importance of Shock Compression in Enhancing ICME’s Geoeffectiveness, Astrophys. J. Lett., 884, L30(7pp), 2019-10. [(527.2KB)] | |
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| 188. | Guo, Jingnan, Robert Wimmer-Schweingruber, Yuming Wang, Manuel Grande, Daniel Matthia, Cary Zeitlin, Bent Ehresmann, and Donald M. Hassler, The pivot energy of solar energetic particles affecting the Martian surface radiation environment, Astrophys. J. Lett., 883, L12(8pp), 2019-09. [(1.55MB)] | |
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| 187. | Liu, Jiajia, Chris J. Nelson, Ben Snow, Yuming Wang, and Robert Erdélyi, Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere, Nat. Comm., 10, 3504, 2019-08. [(5.94MB)] | Abstract. The multi-million degree temperature increase from the middle to the upper solar atmosphere is one of the most fascinating puzzles in plasma-astrophysics. Although magnetic waves might transport enough energy from the photosphere to heat up the local chromosphere and corona, observationally validating their ubiquity has proved challenging. Here, we show observational evidence that ubiquitous Alfvén pulses are excited by prevalent intensity swirls in the solar photosphere. Correlation analysis between swirls detected at different heights in the solar atmosphere, together with realistic numerical simulations, show that these Alfvén pulses propagate upwards and reach chromospheric layers. We found that Alfvén pulses carry sufficient energy flux (1.9 to 7.7 kW m−2) to balance the local upper chromospheric energy losses (~0.1 kW m−2) in quiet regions. Whether this wave energy flux is actually dissipated in the chromosphere and can lead to heating that balances the losses is still an open question.
Acknowledgement: We thank the Science and Technology Facilities Council (STFC, grant numbers ST/M000826/1, ST/L006316/1) for the support to conduct this research. CJN also acknowledges support by STFC consolidated grant ST/P000304/1. YW acknowledges support by NSFC 41774178, 41574165 and 41761134088. Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. Hinode is operated by these agencies in co-operation with ESA and NSC (Norway). The Swedish 1-m Solar Telescope is operated on the island of La Palma by the Institute for Solar Physics of Stockholm University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. The Institute for Solar Physics is supported by a grant for research infrastructures of national importance from the Swedish Research Council (registration number 2017-00625). The SST data was collected as part of the observing time proposal awarded in 2012 to RE as the PI. We thank the SOLARNET for the awarding of the observing time and the data reduction. |
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| 186. | Zhang, Peijin, Chuangbin Wang, Ye Lin, and Yuming Wang, Forward Modeling of the Type III Radio Burst Exciter, Sol. Phys., 294, 62(20pp), 2019-07. | |
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| 185. | Mishra, Wageesh*, Nandita Srivastava*, Yuming Wang*, Zavkiddin Mirtoshev, Jie Zhang, and Rui Liu, Mass Loss via Solar Wind and Coronal Mass Ejections During Solar Cycles 23 and 24, Mon. Not. R. Astron. Soc., 486, 4671-4685, 2019-07. [(1.24MB)] | |
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| 184. | Dumbovic, Mateja, Jingnan Guo, Manuela Temmer, M. Leila Mays, Astrid Veronig, Stephan Heinemann, Karin Dissauer, Stefan Hofmeister, Jasper Halekas, Christian Mostl, Tanja Amerstorfer, Jurgen Hinterreiter, Sasa Banjac, Konstantin Herbst, Yuming Wang, Lukas Holzknecht, Martin Leitner, and Robert F. Wimmer–Schweingruber, Unusual plasma and particle signatures at Mars and STEREO-A related to CME-CME interaction, Astrophys. J., 880, 18(16pp), 2019-07. [(6.33MB)] | |
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| 183. | HU RenXiang, SHAN Xu*, YUAN GuangYuan, WANG ShuWen, ZHANG WeiHang, QI Wei, CAO Zhe, LI YiRen, CHEN ManMing, YANG XiaoPing, WANG Bo, SHAO SiPei, HAO XinJun, FENG ChangQing, SU ZhenPeng, SHEN ChengLong, LI Xin, DAI GuYue, QIU BingLin, PAN ZongHao, LIU Kai, XU ChunKai, LIU ShuBin, AN Qi, ZHANG TieLong, WANG YuMing*, and CHEN XiangJun, A low-energy ion spectrometer with half-space entrance for three-axis stabilized spacecraft, Science China Technological Sciences, 62, 1015-1027, doi:10.1007/s11431-018-9288-8, 2019-06. [(3.83MB)] | Abstract. A low-energy ion spectrometer (LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular- and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90° (–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission.
Acknowledgement. This work was supported by the National Natural Science Foundation of China (Grant No. 41327802), the CAS Key Research Program of Frontier Sciences (Grant No. QYZDB-SSW-DQC015). The authors would like to thank engineers SUN ShuKun, SHI YuFeng, YANG HaiFeng, XIAO Jun-Qiang, ZHANG YuTu, WANG Hui, TANG Yong, XIE Qiong and other people from the Shandong Institute of Space Electronic Technology and China Academy of Space Technology for their help in the fabrication and environmental tests of this payload. We also would like to thank professors ZHU XiaoLong and MA XinWen from the Instritute of Modern Physics, CAS for their valuable assistance in the calibration experiment. |
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| 182. | Zhuo, Zhenjun, Xin Cheng, Lijuan Liu, Yu Dai, Yuming Wang, and Jun Cui, Extreme-ultraviolet Late Phase Caused by Magnetic Reconnection over Quadrupolar Magnetic Configuration in a Solar Flare, Astrophys. J., 878, 46(11pp), 2019-06. [(5.12MB)] | Abstract. A second emission enhancement in warm coronal extreme-ultraviolet (EUV) lines (about 2–7 MK) during some solar flares is known as the EUV late phase. Imaging observations confirm that the late-phase emission originates from a set of longer or higher loops than the main flare loops. Nevertheless, some questions remain controversial: What is the relationship between these two loop systems? What is the heating source of late-phase emission? Does heating accompany the main-phase heating or does it occur quite later? In this paper, we present clear evidence for a heating source in a late-phase solar flare: magnetic reconnection of the overlying field in a quadrupolar magnetic configuration. The event is triggered by an erupted core structure that eventually leads to a coronal mass ejection. A cusp feature and its shrinkage motion high in the late-phase emission region are manifestations of the later phase reconnection following the main flare reconnection. Using the enthalpy-based thermal evolution of loops model, we reasonably reproduce the late-phase emissions in some EUV lines. We suggest that continuous additional heating is responsible for the appearance of the elongated EUV late phase.
We acknowledge the use of the data from GOES, from HMI and AIA instruments on board SDO, and from EUVI instruments on board STEREO. Z.J.Z. is supported by grants from the Open Project of CAS Key Laboratory of Geospace Environment. X.C. is supported by NSFC under grants 11722325, 11733003, and 11790303, and by Jiangsu NSF under grant BK20170011. D.Y. is supported by National
Natural Science Foundation of China under grants 11533005, and 973 Project of China under grant 2014CB744203. Y.M.W. is supported by grants from NSFC (41574165 and 41774178). J.C. is supported by NSFC through grants 41525015 and 41774186. |
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| 181. | Dai, Guyue, Zhenpeng Su, Nigang Liu, Bin Wang, Huinan Zheng, YumingWang, and ShuiWang, Quenching of Equatorial Magnetosonic Waves by Substorm Proton Injections, Geophys. Res. Lett., 46, 6156-6167, 2019-06. [(14.46MB)] | |
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| 180. | Liu, Jiajia, Yuming Wang, and Robert Erdelyi, How Many Twists Do Solar Coronal Jets Release?, Frontiers in Astronomy and Space Sciences, 6, 44, 2019-06. | |
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| 179. | 季海生, 汪毓明, and 汪景琇, 太阳的立体观测, 中国科学－物理学、力学、天文学, , 2019-05. [(424.5KB)] | |
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| 178. | Zhou, Zhenjun, Xin Cheng, Jie Zhang, Yuming Wang, Dong Wang, Lijuan Liu, Bin Zhuang, and Jun Cui, Why do torus-unstable solar filaments experience failed eruptions?, Astrophys. J. Lett., 877, L28(6pp), 2019-05. [(1.75MB)] | Abstract. We study the magnetic field and 3D configuration of 16 filament eruptions during 2010 July–2013 February in order to investigate the factors that control the success and/or failure of solar eruptions. All of these events, i.e., eruptions that failed to be ejected and become coronal mass ejections, have filament maximum heights exceeding 100 Mm. The magnetic field of filament source regions is approximated by a potential field extrapolation method. The filament 3D configuration is reconstructed from three vantage points by the observations of Solar Terrestrial Relations Observatory Ahead/Behind and Solar Dynamics Observatory spacecraft. We calculate the decay index at the apex of these failed filaments and find that in seven cases, their apex decay indexes exceed the theoretical threshold (ncrit = 1.5) of the torus instability (TI). We further determine the orientation change or rotation angle of each filament top during the eruption. Finally, the distribution of these events in the parameter space of rotation angle versus decay index is established. Four distinct regimes in the parameter space are empirically identified. We find that all the torus-unstable cases (decay index n > 1.5) have large rotation angles ranging from 50° to 130°. The possible mechanisms leading to the rotation and failed eruption are discussed. These results imply that, in addition to the TI, the rotation motion during the eruption may also play a significant role in solar eruptions.
We acknowledge the SECCHI, AIA, and HMI consortia for providing excellent observations. Z.J. is supported by the Open Research Program of CAS Key Laboratory of Solar Activity (KLSA201811). X.C. is funded by NSFC grants 11722325, 11733003, 11790303, and 11790300, Jiangsu NSF grants BK20170011, and the Alexander von Humboldt foundation. J. Z. is supported by US NSF AGS-1249270 and NSF AGS-1156120. D.W. acknowledges support by Natural Science Foundation of Anhui Province Education Department (KJ2017A493, gxyq2018030). Y.W. is supported by NSFC grants 41574165, 41761134088, and 41774178. L.L. is supported by the Open Project of CAS Key Laboratory of Geospace Environment, and NSFC grants 11803096. J.C. is supported by NSFC grants 41525015 and 41774186. Z.J. appreciates discussions with and support of Prof. G.P.Zhou, Dr. C.Xia, and Dr. Y.Guo. Software: SolarSoftWare (Freeland & Handy 2012), Paraview (Ahrens et al. 2005; Ayachit 2015). |
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| 177. | Liu, Rui*, Yao Chen, Yuanyong Deng, Mingde Ding, Haisheng Ji, Jun Lin, Hui Tian, Yuming Wang, and Jingxiu Wang*, Recent research progress of solar physics in China, 科学通报, 64, 2011-2024, doi:10.1360/N972019-00286, 2019-05. | |
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| 176. | Cheng, Zhixun, Yuming Wang*, Rui Liu, Zhenjun Zhou, and Kai Liu, Plasma Motion inside Flaring Regions Revealed by Doppler Shift Information from SDO/EVE Observations, Astrophys. J., 875, 93(14pp), 2019-04. [(17.1MB)] | Abstract. Plasma motions within flaring regions provide key information for us to understand the flare processes. Here, we study two X-class flares near the solar disk center, one on 2014 January 7 and the other on 2012 March 7, by using 10 extreme ultraviolet (EUV) emission lines from the Solar Dynamics Observatory/EUV Variability Experiment (EVE). The EVE plasma dynamic spectrum chart, a 2D map of Doppler shift against temperature and time, is constructed based on a spectroscopic analysis of the EUV lines. Three kinds of plasma motion are identified in the plasma dynamic spectrum charts: chromospheric evaporation (100–200 km s−1) above 1 MK, cooling inside postflare loops (approximately 150 km s−1) between 0.3 and 1 MK, and condensation at footpoints (<30 km s−1) below 0.3 MK. We find that the chromospheric evaporation and condensation at footpoints started in the impulsive phase almost simultaneously, while the cooling occurred later in the gradual phase, with a time delay of more than 10 minutes, probably implying the timescale of evaporation movement and heat loss. Atmospheric Imaging Assembly observations and differential emission measure (DEM) analyses suggest that the cooled plasma moves downward within the cold transition region (TR) loops, from top to feet, which are below the hot coronal loops. Besides, the reversal temperature between blue/redshifts is close to 1 MK, implying that the boundary of upflowing/downflowing plasma is located at the lower corona or the upper TR.
We acknowledge use of data from the SDO and GOES spacecraft. SDO is a mission of NASA’s Living With a Star Program. We are grateful to the anonymous referee for valuable and constructive comments. We thank Hui Tian from Peking University for valuable discussion. This work is supported by grants from the NSFC (41574165, 41761134088, 41774178, and 41421063) and the fundamental research funds for the central universities. |
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| 175. | Zhuang, Bin*, Yuming Wang*, Youqiu Hu, Chenglong Shen, Rui Liu, Tingyu Gou, Quanhao Zhang, and Xiaolei Li, Numerical simulations on the deflection of coronal mass ejections in the interplanetary space, Astrophys. J., 876, 73(12pp), 2019-03. [(1.68MB)] | Abstract. Deflection of coronal mass ejections (CMEs) in the interplanetary space, especially in the ecliptic plane, serves as an important factor deciding whether CMEs arrive at the Earth. Observational studies have shown evidence for deflection, whose detailed dynamic processes, however, remain obscure. Here we developed a 2.5D ideal magnetohydrodynamic simulation to study the propagation of CMEs traveling with different speeds in the heliospheric equatorial plane. The simulation confirms the existence of the CME deflection in the interplanetary space, which is related to the difference between the CME speed (vr) and the solar wind speed (vsw): a CME will propagate radially as vr is close to vsw but eastward or westward when vr is larger or smaller than vsw; the greater the difference is, the larger the deflection angle will be. This result supports the model for CME deflection in the interplanetary space (DIPS) proposed by Wang et al., predicting that an isolated CME can be deflected due to the pileup of solar wind plasma ahead of or behind the CME. Furthermore, the deflection angles, which are derived by inputting vr and vsw from the simulation into the DIPS model, are found to be consistent with those in the simulation.
This work was supported the grants from NSFC (41774178, 41574165, 41274173, and 41804161), and the fundamental research funds for the central universities. We also acknowledge funds from Key Laboratory of Space Weather, National Center for Space Weather, China Meteorological Administration. |
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| 174. | Gou, Tingyu, Rui Liu*, Bernhard Kliem*, Yuming Wang, and Astrid M. Veronig, The birth of a coronal mass ejection, Science Advances, 5, eaau7004, 2019-03. [(1.6MB)] | |
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| 173. | Awasthi, Arun Kumar, Rui Liu, and Yuming Wang, Double-decker Filament Configuration Revealed by Mass Motions, Astrophys. J., 872, 109(11pp), doi:10.3847/1538-4357/aafdad, 2019-02. [(8.91MB)] | Abstract. It is often envisaged that dense filament material lies in the dips of magnetic field lines belonging to either a sheared arcade or a magnetic flux rope. But it is also debated which configuration correctly depicts filaments’ magnetic structure, due to our incapacity to measure the coronal magnetic field. In this paper, we address this issue by employing mass motions in an active-region filament to diagnose its magnetic structure. The disturbance in the filament was driven by a surge initiated at the filament’s eastern end in the NOAA active region 12685, which was observed by the 1 m New Vacuum Solar Telescope in the Hα line-center and line wing (±0.4 Å). Filament material predominately exhibits two kinds of motions, namely, rotation about the spine and longitudinal oscillation along the spine. The former is evidenced by antisymmetric Doppler shifts about the spine; the latter features a dynamic barb with mass extending away from the Hα spine until the transversal edge of the EUV filament channel. The longitudinal oscillation in the eastern section of the filament is distinct from that in the west, implying that the underlying field lines have different lengths and curvature radii. The composite motions of filament material suggest a double-decker host structure with mixed signs of helicity, comprising a flux rope atop a sheared-arcade system.
A.K.A. acknowledges the support from the Chinese Academy of Science (CAS) as well as the International Postdoctoral Program of University of Science and Technology of China. R.L. acknowledges the support from NSFC 41474151, 41774150, and 41761134088. This investigation made use of the data acquired from NVST, which is operated by Yunnan Astronomical Observatory, China. A.K.A. acknowledges the hospitality offered by the staff of Fuxian Solar Observatory during his stay for the observing period and Dr. Y. Y. Xiang for helping with the alignment of NVST images. The authors also acknowledge the free data usage policy of SDO, GOES, and GONG Hα network. Software: MPFIT (Markwardt 2009). |
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| 172. | Liu, Nigang, Zhenpeng Su*, Zhonglei Gao, Huinan Zheng, Yuming Wang, and Shui Wang, Magnetospheric Chorus, Exohiss, and Magnetosonic Emissions Simultaneously Modulated by Fundamental Toroidal Standing Alfvén Waves Following Solar Wind Dynamic Pressure Fluctuations, Geophys. Res. Lett., 46, 1900-1910, doi:10.1029/2018GL081500, 2019-02. [(5.27MB)] | |
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| 171. | Liu, Rui*, Yuming Wang, Jeongwoo Lee, and Chenglong Shen, Impacts of EUV Wavefronts on Coronal Structures in Homologous Coronal Mass Ejections, Astrophys. J., 870, 15(18pp), 2019-01. [(25.43MB)] | Abstract. Large-scale propagating fronts are frequently observed during solar eruptions, yet whether or not they are waves is an open question, partly because the propagation is modulated by coronal structures, whose magnetic fields we still cannot measure. However, when a front impacts coronal structures, an opportunity arises for us to look into the magnetic properties of both interacting parties in the low-β corona. Here we studied large-scale EUV fronts accompanying three coronal mass ejections (CMEs), each originating from a kinking rope-like structure in the NOAA active region (AR) 12371. These eruptions were homologous and the surrounding coronal structures remained stationary. Hence we treated the events as one observed from three different viewing angles, and found that the primary front directly associated with the CME consistently transmits through (1) a polar coronal hole, (2) the ends of a crescent-shaped equatorial coronal hole, leaving a stationary front outlining its AR-facing boundary, and (3) two quiescent filaments, producing slow and diffuse secondary fronts. The primary front also propagates along an arcade of coronal loops and slows down due to foreshortening at the far side, where local plasma heating is indicated by an enhancement in 211Å (Fe XIV) but a dimming in 193Å (Fe XII) and 171Å (Fe IX). The strength of coronal magnetic field is therefore estimated to be ∼2G in the polar coronal hole and ∼4G in the coronal arcade neighboring the AR. These observations substantiate the wave nature of the primary front and shed new light on slow fronts.
The authors thank the anonymous referee for critical comments and constructive suggestions that helped improve the manuscript. R.L. acknowledges support by NSFC 41474151, 41774150, and 41761134088. Y.W. acknowledges support by NSFC 41131065 and 41574165. J.L. was supported by the NSFC grants 41331068, 11790303 (11790300), and 41774180. This work was also supported by NSFC 41421063, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. |
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| 170. | Chi, Yutian, Chenglong Shen, Bingxian Luo, Yuming Wang, and Mengjiao Xu, Geoeffectiveness of Stream Interaction Regions from 1995 to 2016, Space Weather, 16, 1960-1971, 2018-12. [(2.2MB)] | Abstract. Stream interaction regions (SIRs) are important sources of geomagnetic storms. In this work, we first extend the end time of the widely used SIR catalog developed by Jian et al. (2006, https://doi.org/10.1007/s11207-006-0132-3), which covered the period from 1995 to 2009, to the end of 2016. Based on this extended SIR catalog, the geoeffectiveness of SIRs is discussed in detail. It was found that 52% of the SIRs caused geomagnetic storms with Dstmin ≤ −30 nT, but only 3% of them caused intense geomagnetic storms with Dstmin ≤ −100 nT. Furthermore, we found that 10 of the intense geomagnetic storms caused by SIRs were associated with complex structures due to interactions between SIRs and interplanetary coronal mass ejections (ICMEs). In such a structure, an ICME is embedded in the SIR and located between the slow and fast solar wind streams. In addition, we found that the geoeffectiveness of SIRs interacting with ICMEs is enhanced. The possibility of SIR-ICME interaction structures causing geomagnetic storms is markedly higher than that of isolated SIRs or isolated ICMEs. In particular, the geoeffectiveness of SIR-ICME interaction structures is similar to that of the Shock-ICME interaction structures, which have been demonstrated to be the main causes of geomagnetic storms.
We acknowledge the use of the data from Wind satellites and the world data center (WDC) for Geomagnetism, Kyoto. The Wind/MFI, Wind/SWE, Wind/SFPD, and Wind/3DP data are downloaded from the NASA’s Space Physics Data Facility (SPDF, http://spdf.gsfc.nasa.gov/). The Dst indices came from the link http://wdc.kugi.kyoto-u.ac.jp/. The yearly sunspot number data locate at Royal Observatory of Belgium via the link http://www.sidc.be/silso/datafiles. We are grateful to the 1996–2009 JL SIR list from the link http://www-ssc.igpp.ucla.edu/∼jlan/ACE/Level3/SIR_List_from_Lan_Jian.pdf. This work is supported by grants from CAS (Youth Innovation Promotion Association CAS and Key Research Program of Frontier Sciences QYZDB-SSW-DQC015), NSFC (41774181 and 41474164), the Fundamental Research Funds for the Central Universities, and the Specialized Research Fund for State Key Laboratories. Y. M. is also supported by the NSFC grants(41574165 and 41774178). The authors also wish to thank the Editor M. Hapgood and two unknown referees who took the time to scrutinize carefully the successive versions of this paper and, by many suggestions, contributed to improving the final version. |
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| 169. | Dong Wang, Rui Liu, Yuming Wang, Tingyu Gou, Quanhao Zhang, Zhenjun Zhou, and Min Zhang, Unraveling the links among sympathetic eruptions, Astrophys. J., 869, 177(10pp), 2018-12. [(13.08MB)] | Abstract. Solar eruptions occurring at different places within a relatively short time interval are considered to be sympathetic. However, it is difficult to determine whether there exists a cause and effect between them. Here we study a failed and a successful filament eruption following an X1.8-class flare on 2014 December 20, in which slipping-like magnetic reconnections serve as a key causal link among the eruptions. Reconnection signatures and effects are identified as follows: at both sides of the filament experiencing the failed eruption, serpentine ribbons extend along the chromospheric network to move away from the filament, while a hot loop apparently grows above it; at the filament undergoing the successful eruption, overlying cold loops contract, while coronal dimming appears at both sides even before the filament eruption. These effects are understood by reconnections continually transforming magnetic fluxes overlying one filament to the other, which adjusts how the magnetic field decays with increasing height above the filaments in opposite trends, therefore either strengthening or weakening the magnetic confinement of each filament.
D.W. acknowledges support by Natural Science Foundation of Anhui Province Education Department (KJ2017A493, KJ2017A491, gxyq2018030) and NSFC 11704003. R.L. acknowledges support by NSFC 41474151, 41774150, and 41761134088. Y.W. acknowledges support by NSFC 41774178 and 41574165. M.Z. acknowledges support by Natural Science Foundation of Anhui Province Education Department (KJ2016JD24) and Anhui Province Quality Engineering (2017zhkt161). This work is also supported by NSFC 41421063, CAS Key Research Program of Frontier Sciences QYZDB-SSW-DQC015, and the fundamental research funds for the central universities. Software: SolarSoftWare (Freeland & Handy 2012). |
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| 168. | Zhao, Ake*, Yuming Wang*, Hengqiang Feng, Mengjiao Xu, Yan Zhao, Guoqing Zhao, and Qiang Hu, The twist profile in the cross-section of interplanetary magnetic clouds, Astrophys. J. Lett., 869, L13(6pp), 2018-12. [(625.9KB)] | Abstract. Magnetic flux ropes (MFRs) as a well-organized magnetic field structure embedded in space plasmas have been widely studied for several decades. The twists of magnetic field lines in MFRs can yield much information regarding the formation and stability of MFRs, yet there is still open debate about them. Here, with the aid of a uniform-twist force-free flux rope model, we study the twist profile in the cross section of a interplanetary magnetic cloud (MC) by peeling off equal azimuthal mgnetic flux layer by layer from the outermost shell, just like peeling an onion. The absolute value of the average twist, t, and the twist in each layer, τ, exhibit an almost monotonous decrease from the axis to the periphery of the MC, but τ has a larger relative error. However, they do have a coincident trend of a high-twist core and an low-twist outer shell. The twist number per unit length, t/τ, follows a linear trend versus l/Rpi, where R is the radius of each layer, with a correlation coefficient of 0.96/0.91 and slope of 0.27/0.26, which is well below the critical slope of 1 suggested by Wang et al.
We acknowledge the use of data from the Wind spacecraft. This research is supported by NSFC grants 41804163, 41774178, 41761134088, 41574165, and 41674170. |
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| 167. | Gao, Zhonglei, Zhenpeng Su, Fuliang Xiao, Danny Summers, Nigang Liu, Huinan Zheng, Yuming Wang, Fengsi Wei, and Shui Wang, Nonlinear coupling between whistler-mode chorus and electron cyclotron harmonic waves in the magnetosphere, Geophys. Res. Lett., 45, 12685-12693, 2018-12. [(7.1MB)] | |
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| 166. | Li, Xiaolei, Yuming Wang*, Rui Liu, Chenglong Shen, Quanhao Zhang, Bin Zhuang, Jiajia Liu, and Yutian Chi, Reconstructing solar wind inhomogeneous structures from stereoscopic observations in white-light: Small transients along the Sun-Earth line, J. Geophys. Res. - Space Phys., 123, 7257-7270, doi:10.1029/2018JA025485, 2018-10. [(11.47MB)] | Abstract. The Heliospheric Imagers (HI) onboard the two spacecraft of the Solar Terrestrial Relations Observatory (STEREO) provided white-light images of transients in the solar wind from dual perspectives from 2007 to 2014. In this paper, we develop a new method to identify and locate the transients automatically from simultaneous images from the two inner telescopes, known as HI-1, based on a correlation analysis. Correlation coefficient (cc) maps along the Sun-Earth line are constructed for the period from 1 January 2010 to 28 February 2011. From the maps, transients propagating along the Sun-Earth line are identified, and a 27-day periodic pattern is revealed, especially for small-scale transients. Such a periodicity in the transient pattern is consistent with the rotation of the Sun’s global magnetic structure and the periodic crossing of the streamer structures and slow solar wind across the Sun-Earth line, and this substantiates the reliability of our method and the high degree of association between the small-scale transients of the slow solar wind and the coronal streamers. Besides, it is suggested by the cc map that small-scale transients along the Sun-Earth line are more frequent than large-scale transients by a factor of at least 2, and that they quickly diffused into background solar wind within about 40 Rs in terms of the signal-to-noise ratio of white-light emissions. The method provides a new tool to reconstruct inhomogeneous structures in the heliosphere from multiple perspectives.
The STEREO/SECCHI data are produced by a consortium of NRL (USA), RAL (UK), LMSAL (USA), GSFC (USA), MPS (Germany), CSL (Belgium), IOTA (France), and IAS (France). The SECCHI data presented in this paper were obtained from STEREO Science Center (https://stereo-ssc.nascom.nasa.gov/data/ins_data/secchi_hi/L2/). The Wind data were obtained from the Space Physics Data Facility (https://cdaweb.sci.gsfc.nasa.gov/). This work is supported by the grants from NSFC (41574165, 41774178, and 41761134088) and the Fundamental Research Funds for the Central Universities (WK2080000077). |
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| 165. | Su, Zhenpeng, Nigang Liu, Huinan Zheng, Yuming Wang, and Shui Wang, Multipoint observations of nightside plasmaspheric hiss generated by substorm injected electrons, Geophys. Res. Lett., 45, doi:10.1029/2018GL079927, 2018-10. [(6.96MB)] | |
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| 164. | Liu, Lijuan, Xin Cheng, Yuming Wang, Zhenjun Zhou, Yang Guo, and Jun Cui, Rapid Buildup of a Magnetic Flux Rope during a Confined X2.2 Class Flare in NOAA AR 12673, Astrophys. J. Lett., 867, L5, 2018-10. [(8.61MB)] | Abstract. Magnetic flux ropes (MFRs) are believed to be the core structure in solar eruptions; nevertheless, their formation remains intensely debated. Here we report a rapid buildup process of an MFR system during a confined X2.2 class flare occurred on 2017 September 6 in NOAA active region (AR) 12673, three hours after which the structure erupted to a major coronal mass ejection (CME) accompanied by an X9.3 class flare. For the X2.2 flare, we do not find extreme ultraviolet dimmings, separation of its flare ribbons, or clear CME signatures, suggesting a confined flare. For the X9.3 flare, large-scale dimmings, separation of flare ribbons, and a CME show it to be eruptive. By performing a time sequence of nonlinear force-free fields extrapolations we find the following. Until the eruptive flare, an MFR system was located in the AR. During the confined flare, the axial flux and the lower bound of the magnetic helicity for the MFR system were dramatically enhanced by about 86% and 260%, respectively, although the mean twist number was almost unchanged. During the eruptive flare, the three parameters were all significantly reduced. The results evidence the buildup and release of the MFR system during the confined and the eruptive flare, respectively. The former may be achieved by flare reconnection. We also calculate the pre-flare distributions of the decay index above the main polarity inversion line and find no significant difference. It indicates that the buildup of the magnetic flux and helicity of the MFR system may play a role in facilitating its final eruption.
We thank our anonymous referee for constructive comments that significantly improved the manuscript. We thank Jie Zhang for his helpful discussions. We acknowledge the data from GOES, SDO, and SOHO. L.L. is supported by the Open Project of CAS Key Laboratory of Geospace Environment, and NSFC (11803096). X.C. is funded by NSFC (11722325, 11733003, 11790303, 11790300), Jiangsu NSF (BK20170011), and “Dengfeng B” program of Nanjing University. Y.W. is supported by NSFC (41574165, 41774178). Y.G. is supported by NSFC (11773016, 11533005) and the fundamental research funds for the central universities 020114380028. J.C. is supported by NSFC (41525015, 41774186). |
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| 163. | Mishra, Wageesh* and Yuming Wang*, Modeling the thermodynamic evolution of Coronal Mass Ejections using their kinematics, Astrophys. J., 865, 50(15pp), 2018-09. [(845.9KB)] | Abstract. Earlier studies on coronal mass ejections (CMEs), using remote sensing and in situ observations, have attempted to determine some internal properties of CMEs, which were limited to a certain position or a certain time. To understand the evolution of the internal thermodynamic state of CMEs during their heliospheric propagation, we improve the self-similar flux-rope internal state model, which is constrained by the measured propagation and expansion speed profiles of a CME. We implement the model in a CME that erupted on 2008 December 12 and probe the internal state of the CME. It is found that the polytropic index of the CME plasma decreased continuously from 1.8 to 1.35 as the CME moved away from the Sun, implying that the CME released heat before it reached an adiabatic state and then absorbed heat. We further estimate the entropy changing and heating rate of the CME. We also find that the thermal force inside the CME is the internal driver of CME expansion while the Lorentz force prevented the CME from expanding. It is noted that the centrifugal force due to poloidal motion decreased at the fastest rate, and the Lorentz force decreased slightly faster than the thermal pressure force as the CME moved away from the Sun. We also discuss the limitations of the model and approximations made in the study.
We acknowledge the UK Solar System Data Center (UKSSDC) for providing the STEREO/COR2 data. Y.W. is supported by the National Natural Science Foundation of China (NSFC) grant Nos. 41574165, 41774178, and 41761134088. W.M. is supported by NSFC grant No. 41750110481 and the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) grant No. 2015PE015. W.M. thanks Ying D. Liu (CAS, China) for the helpful discussion. |
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| 162. | Gao, ZhongLei, ZhenPeng Su, FuLiang Xiao, HuiNan Zheng, YuMing Wang, Shui Wang, H. E. Spence, G. D. Reeves, D. N. Baker, J. B. Blake, and H. O. Funsten, Exohiss wave enhancement following substorm electron injection in the dayside magnetosphere, Earth & Planet. Phys., 2, 359-370, doi:, 2018-09. [(6.92MB)] | |
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| 161. | Guo, Jingnan, Mateja Dumbovic, Robert F. Wimmer-Schweingruber, Manuela Temmer, Henning Lohf, Yuming Wang, Astrid Veronig, Donald M. Hassler, Leila M. Mays, Cary Zeitlin, Bent Ehresmann, Oliver Witasse, Johan L. Freiherr von Forstner, Bernd Heber, and Mats Holmstrom, Modeling the evolution and propagation of 10 September 2017 CMEs and SEPs arriving at Mars constrained by remote sensing and in situ measurement, Space Weather, 16, 1156-1169, doi:10.1029/2018SW001973, 2018-08. [(2.29MB),  (934.7KB)] | Abstract. On 10 September 2017, solar energetic particles originating from the active region 12673 produced a ground level enhancement at Earth. The ground level enhancement on the surface of Mars, 160 longitudinally east of Earth, observed by the Radiation Assessment Detector (RAD) was the largest since the landing of the Curiosity rover in August 2012. Based on multipoint coronagraph images and the Graduated Cylindrical Shell model, we identify the initial 3-D kinematics of an extremely fast coronal mass ejection (CME) and its shock front, as well as another two CMEs launched hours earlier with moderate speeds. The three CMEs interacted as they propagated outward into the heliosphere and merged into a complex interplanetary CME (ICME). The arrival of the shock and ICME at Mars caused a very significant Forbush decrease seen by RAD only a few hours later than that at Earth, which was about 0.5 AU closer to the Sun. We investigate the propagation of the three CMEs and the merged ICME together with the shock, using the drag-based model and the WSA-ENLIL plus cone model constrained by the in situ observations. The synergistic study of the ICME and solar energetic particle arrivals at Earth and Mars suggests that to better predict potentially hazardous space weather impacts at Earth and other heliospheric locations for human exploration missions, it is essential to analyze (1) the eruption of the flare and CME at the Sun, (2) the CME kinematics, especially during their interactions, and (3) the spatially and temporally varying heliospheric conditions, such as the evolution and propagation of the stream interaction regions.
We acknowledge use of NASA/SPDF OMNIWeb service and OMNI data, EU NMDB database (www.nmdb.eu), STEREO data (https://stereo-ssc.nascom.nasa.gov/), and NOAA GOES data (https://satdat.ngdc.noaa.gov/). ENLIL with Cone Model was developed by D. Odstrcil at George Mason University. MSL RAD is supported by NASA (HEOMD) under JPL subcontract 1273039 to SWRI, and in Germany by DLR (under German Space Agency grants 50QM0501, 50QM1201, and 50QM1701) to the Christian-Albrechts-University of Kiel. RAD data are archived in the NASA planetary data systems’ planetary plasma interactions node (http://ppi.pds.nasa.gov/). The Swedish contribution to the ASPERA-3 experiment is supported by the Swedish National Space Board. ASPERA-3 data are public at the ESA Planetary Science Archive. M. D. acknowledges funding from the EU H2020 MSCA grant agreement (745782). M. T. acknowledges the support by the FFG/ASAP program under grant 859729 (SWAMI). Y. W. is supported by the grants from NSFC (41574165 and 41774178). A. M. V. acknowledges support from the Austrian Science Fund (FWF): P27292-N20. J. G. thanks Christina Lee, Andreas Klassen, Fernando Carcaboso, Nina Dresing, and Andreas Taut for helpful advices and discussions. J. G. and R. F.W. S. acknowledge discussions during various ISSI team meetings. |
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| 160. | Wang, Jingjing, Xianzhi Ao, Yuming Wang, Chuanbing Wang, Yanxia Cai, Bingxian Luo, Siqing Liu, Chenglong Shen, Bin Zhuang, Xianghui Xue, and Jiancun Gong, An operational solar wind prediction system transitioning fundamental science to operations, J. Space Weather Space Clim., 8, A39, 2018-08. [(8.49MB)] | Abstract. We present in this paper an operational solar wind prediction system. The system is an outcome of the collaborative efforts between scientists in research communities and forecasters at Space Environment Prediction Center (SEPC) in China. This system is mainly composed of three modules: (1) a photospheric magnetic field extrapolation module, along with the Wang-Sheeley-Arge (WSA) empirical method, to obtain the background solar wind speed and the magnetic field strength on the source surface; (2) a modified Hakamada-Akasofu-Fry (HAF) kinematic module for simulating the propagation of solar wind structures in the interplanetary space; and (3) a coronal mass ejection (CME) detection module, which derives CME parameters using the ice-cream cone model based on coronagraph images. By bridging the gap between fundamental science and operational requirements, our system is finally capable of predicting solar wind conditions near Earth, especially the arrival times of the co-rotating interaction regions (CIRs) and CMEs. Our test against historical solar wind data from 2007 to 2016 shows that the hit rate (HR) of the high-speed enhancements (HSEs) is 0.60 and the false alarm rate (FAR) is 0.30. The mean error (ME) and the mean absolute error (MAE) of the maximum speed for the same period are 73.9 km s-1 and 101.2 km s-1, respectively. Meanwhile, the ME and MAE of the arrival time of the maximum speed are 0.15 days and 1.27 days, respectively. There are 25 CMEs simulated and the MAE of the arrival time is 18.0 h.
We thank the SOHO LASCO instrument team for providing the coronal observations. We also thank the ACE MAG and SWEPAM instrument team and ACE science data center for providing their data. This work is supported by the National Natural Science Foundation of China (Grant No. 41604149, 41474164, 41574165, 41761134088, 41574167, 41774181), and by the Youth Innovation Promotion Association CAS. The editor thanks two anonymous referees for their assistance in evaluating this paper. |
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| 159. | Liu, Nigang, Zhenpeng Su, Huinan Zheng, Yuming Wang, and Shui Wang, Magnetosonic harmonic falling and rising frequency emissions potentially generated by nonlinear wave-wave interactions in the Van Allen radiation belts, Geophys. Res. Lett., 45, doi:10.1029/2018GL079232, 2018-08. [(30.34MB)] | |
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| 158. | 章伟杭, 郝新军, 李毅人, 王淑文, 封常青, 陈满明, 杨小平, 胡任翔, 单旭, and 汪毓明*, 半空间低能离子谱仪高压电源设计, 核电子学与探测技术, , 459-463, 2018-08. | |
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| 157. | Chi, Yutian, Zhang, Jie, Shen, Chenglong, Hess, Phillip, Liu, Lijuan, Mishra, Wageesh, and Wang, Yuming, Observational Study of an Earth-affecting Problematic ICME from STEREO, Astrophys. J., 863, 108(13pp), 2018-08. [(2.33MB)] | Abstract. We present a study of the origin of one interplanetary coronal mass ejection (ICME) that lacked an easily identifiable signature of an associated progenitor coronal mass ejection (CME) near the Sun in the observations of SOHO/LASCO at the L1 point. We consider these kinds of ICMEs as problematic, as they pose the difficulty of understanding the Sun–Earth connection and providing space weather warnings; understanding the causes of problematic ICMEs is important for space weather forecasting. This study presents the first detailed analysis of a geoeffective problematic ICME that occurred on 2011 May 28, whose progenitor CMEs are difficult to identify in LASCO images, but fortunately they were captured by SECCHI on board the STEREO spacecraft in the quadrature configuration. There are two progenitor CMEs launching from the Sun in succession of 8 hours. We apply the graduated cylindrical shell model to reconstruct the 3D geometry, propagating direction, velocity, and brightness of the two CMEs. The main cause of the first CME (CME-1) invisible in SOHO/LASCO is due to its low mass; that is, when the CME emerges above the occulter, its brightness is as faint as the noise. The second CME (CME-2) is small, including a narrow angular width and a small cross-section of the magnetic flux rope. Even though propagating toward the Earth, CME-2 appeared as a narrow CME instead of as a halo or partial halo CME in the LASCO field of view. We also show that CME-2 propagates faster than CME-1, and that they might have interacted in the interplanetary space.
We acknowledge the use of data from the SOHO, STEREO, and Wind spacecraft. STEREO is the third mission in NASA’s Solar Terrestrial Probes program, and SOHO is a project of international cooperation between the ESA and NASA. This work is supported by NSFC 41774181 and Youth Innovation Promotion Association CAS. J.Z. is supported by US NSF AGS-1249270 and NSF AGS-1156120. |
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| 156. | Liemohn, Michael W., Yuming Wang, Alan Rodger, Michael Balikhin, and Larry Kepko, Editorial: Thank you to the 2017 JGR Space Physics reviewers, J. Geophys. Res. - Space Phys., 123, 4510-4516, 2018-07. [(425.7KB)] | |
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| 155. | Liu, Rui, Jun Chen, and Yuming Wang, Disintegration of an Eruptive Filament via Interactions with Quasi-Separatrix Layers, Science China: Physics, Mechanics & Astronomy, 61, 069611, 2018-06. [(9.08MB)] | Abstract. The disintegration of solar filaments via mass drainage is a frequently observed phenomenon during a variety of filament activities. It is generally considered that the draining of dense filament material is directed by both gravity and magnetic field, yet the detailed process remains elusive. Here we report on a partial filament eruption during which filament material drains downward to the surface not only along the filament’s legs, but to a remote flare ribbon through a fan-out curtain-like structure. It is found that the magnetic configuration is characterized by two conjoining dome-like quasi-sepratrix layers (QSLs). The filament is located underneath one QSL dome, whose footprint apparently bounds the major flare ribbons resulting from the filament eruption, whereas the remote flare ribbon matches well with the other QSL dome’s far-side footprint. We suggest that the interaction of the filament with the overlying QSLs results in the splitting and disintegration of the filament.
This work was supported by the National Natural Science Foundation of China (Grant Nos. 41474151, 41774150, and 41421063), the Thousand
Young Talents Program of China, CAS Key Research Program of Frontier Sciences of (Grant No. QYZDB-SSW-DQC015), and the Fundamental Research
Funds for the Central Universities. |
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| 154. | Wang, Yuming*, Chenglong Shen, Rui Liu, Jiajia Liu, Jingnan Guo, Xiaolei Li, Mengjiao Xu, Qiang Hu, and Tielong Zhang, Understanding the twist distribution inside magnetic flux ropes by anatomizing an interplanetary magnetic cloud, J. Geophys. Res. - Space Phys., 123, 3238-3261, doi:10.1002/2017JA024971, 2018-06. [(1.48MB), (8.19MB), (8.15MB)] | Abstract. Magnetic flux rope (MFR) is the core structure of the greatest eruptions, that is, the coronal mass ejections (CMEs), on the Sun, and magnetic clouds are posteruption MFRs in interplanetary space. There is a strong debate about whether or not a MFR exists prior to a CME and how the MFR forms/grows through magnetic reconnection during the eruption. Here we report a rare event, in which a magnetic cloud was observed sequentially by four spacecraft near Mercury, Venus, Earth, and Mars, respectively. With the aids of a uniform-twist flux rope model and a newly developed method that can recover a shock-compressed structure, we find that the axial magnetic flux and helicity of the magnetic cloud decreased when it propagated outward but the twist increased. Our analysis suggests that the “pancaking” effect and “erosion” effect may jointly cause such variations. The significance of the pancaking effect is difficult to be estimated, but the signature of the erosion can be found as the imbalance of the azimuthal flux of the cloud. The latter implies that the magnetic cloud was eroded significantly leaving its inner core exposed to the solar wind at far distance. The increase of the twist together with the presence of the erosion effect suggests that the posteruption MFR may have a high-twist core enveloped by a less-twisted outer shell. These results pose a great challenge to the current understanding on the solar eruptions as well as the formation and instability of MFRs.
We acknowledge the use of the data from the magnetometers on board the MESSENGER, VEX, andWind spacecraft, the Solar Wind Experiment (SWE) on boardWind spacecraft, the RAD on board the MSL, and EUV imagers and coronagraphs on board the Solar Dynamics Observatory (SDO), Solar and Heliospheric Observatory (SOHO), and the twin Solar Terrestrial Relations Observatories (STEREO).We do
appreciate the constructive comments from anonymous referees. which make the paper much better. Y. W. is grateful to the valuable discussion with Hui Li from Los Alamos National Laboratory about the astrophysical jets and high-twist phenomena. J. G. acknowledges stimulating discussions with the ISSI team “Radiation Interactions at Planetary Bodies” and thanks ISSI for its hospitality. Y. W. acknowledges the support from NSFC grants 41774178 and 41574165, R. L. the support from NSFC grants
41474151 and 41774150 and the Thousand Young Talents Program of
China, J. L. the support from the Science and Technology Facility
Council (STFC) of UK, and Q. H. partial support from NASA grant NNX14AF41G and NRL contract N00173-14-1-G006. This work is also supported by NSFC grants 41761134088 and 41421063 and the fundamental research funds for the central universities. |
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| 153. | Shen, Chenglong, Mengjiao Xu, Yuming Wang, Yutian Chi, and Bingxian Luo, Why the Shock-ICME Complex Structure Is Important: Learning from the Early 2017 September CMEs, Astrophys. J., 861, 28(9pp), 2018-06. [(17.81MB)] | Abstract. In the early days of 2017 September, an exceptionally energetic solar active region AR 12673 aroused great interest in the solar physics community. It produced four X class flares, more than 20 coronal mass ejections (CMEs), and an intense geomagnetic storm, for which the peak value of the Dst index reached up to −142 nT at 2017 September 8 02:00 UT. In this work, we check the interplanetary and solar source of this intense geomagnetic storm. We find that this geomagnetic storm was mainly caused by a shock-interplanetary CME (ICME) complex structure, which was formed by a shock driven by the 2017 September 6 CME propagating into a previous ICME, which was the interplanetary counterpart of the 2017 September 4 CME. To better understand the role of this structure, we conduct a quantitative analysis on the enhancement of ICME’s geoeffectiveness induced by the shock compression. The analysis shows that the shock compression enhanced the intensity of this geomagnetic storm by a factor of two. Without shock compression, there would have been only a moderate geomagnetic storm with a peak Dst value of ∼−79 nT. In addition, the analysis of the proton flux signature inside the shock-ICME complex structure shows that this structure also enhanced the solar energetic particle intensity by a factor of approximately five. These findings illustrate that the shock-ICME complex structure is a very important factor in solar physics study and space weather forecast.
The authors thank the referee for comments that helped to improve this paper. We acknowledge the use of the data from
SOHO, STEREO, Wind, DSCOVR, and GOES satellites and the world data center (WDC) for Geomagnetism, Kyoto. This work is
supported by grants from CAS (Youth Innovation Promotion Association CAS and Key Research Program of Frontier Sciences QYZDB-SSW-DQC015), NSFC (41774181, 41774178, 41574165, 41474164, 41761134088), the Fundamental Research Funds for the Central Universities (WK2080000077), and the Specialized Research Fund for State Key Laboratories. |
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| 152. | Liu, Lijuan*, Yuming Wang*, Zhenjun Zhou, Karin Dissauer, Manuela Temmer, and Jun Cui, A Comparative Study between a Failed and a Successful Eruption Initiated from the Same Polarity Inversion Line in AR 11387, Astrophys. J., 858, 121(14pp), 2018-05. [(1.2MB), (4.59MB)] | Abstract. In this paper, we analyzed a failed and a successful eruption that initiated from the same polarity inversion line within NOAA AR 11387 on 2011 December 25. They both started from a reconnection between sheared arcades, with distinct pre-eruption conditions and eruption details: before the failed one, the magnetic fields of the core region had a weaker non-potentiality; the external fields had a similar critical height for torus instability, and a similar local torus-stable region, but a larger magnetic flux ratio (of low corona and near-surface region) compared to the successful one. During the failed eruption, a smaller Lorentz force impulse was exerted on the outward ejecta; the ejecta had a much slower rising speed. Factors that might lead to the initiation of the failed eruption are identified: (1) a weaker non-potentiality of the core region, and a smaller Lorentz force impulse gave the ejecta a small momentum; (2) the large flux ratio, and the local torus-stable region in the corona provided strong confinements that made the erupting structure regain an equilibrium state.
We thank our anonymous referee for his/her valuable comments that helped to improve this paper. We acknowledge the use of the data from GOES, from HMI and AIA instruments on board SDO, and from the EUVI, COR1, and COR2 instruments on board STEREO. L.L. is supported by the grants from the Open Project of CAS Key Laboratory of Geospace Environment. Y.W. is supported by grants from NSFC (41574165 and 41774178). K.D. acknowledges the support by the Austrian Space Applications Program of the Austrian Research Promotion Agency FFG (ASAP-11 4900217). M.T. acknowledges support by the FFG/ASAP Programme under grant No. 859729 (SWAMI). J.C. is supported by NSFC through grants 41525015 and 41774186. |
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| 151. | Zhuang, Bin, Youqiu Hu, Yuming Wang, Quanhao Zhang, Rui Liu, Tingyu Gou, and Chenglong Shen, Coronal flux rope catastrophe associated with internal energy release, J. Geophys. Res. - Space Phys., 123, 2513-2519, 2018-04. [(568.8KB)] | Abstract. Magnetic energy during the catastrophe was predominantly studied by the previous catastrophe works since it is believed to be the main energy supplier for the solar eruptions. However, the contribution of other types of energies during the catastrophe cannot be neglected. This paper studies the catastrophe of the coronal flux rope system in the solar wind background, with emphasis on the transformation of different types of energies during the catastrophe. The coronal flux rope is characterized by its axial and poloidal magnetic fluxes and total mass. It is shown that a catastrophe can be triggered by not only an increase but also a decrease of the axial magnetic flux. Moreover, the internal energy of the rope is found to be released during the catastrophe so as to provide energy for the upward eruption of the flux rope. As far as the magnetic energy is concerned, it provides only part of the energy release, or even increases during the catastrophe, so the internal energy may act as the dominant or even the unique energy supplier during the catastrophe.
This work was supported by the grants from NSFC (41774178, 41574165, 41421063, and 41274173), and the fundamental research funds for the central universities. The data and code scripts used in this paper can be found online at https://doi.org/10.6084/m9.figshare.5955616. |
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| 150. | Awasthi, Arun Kumar, Rui Liu, Haimin Wang, Yuming Wang, and Chenglong Shen, Pre-eruptive Magnetic Reconnection within a Multi-flux-rope System in the Solar Corona, Astrophys. J., 857, 124(13pp), 2018-04. [(6.95MB)] | Abstract. The solar corona is frequently disrupted by coronal mass ejections (CMEs), whose core structure is believed to be a flux rope made of helical magnetic field. This has become a “standard” picture; though, it remains elusive how the flux rope forms and evolves toward eruption. While one-third of the ejecta passing through spacecraft demonstrate a flux-rope structure, the rest have complex magnetic fields. Are they originating from a coherent flux rope, too? Here we investigate the source region of a complex ejecta, focusing on a flare precursor with definitive signatures of magnetic reconnection, i.e., nonthermal electrons, flaring plasma, and bidirectional outflowing blobs. Aided by nonlinear force-free field modeling, we conclude that the reconnection occurs within a system of multiple braided flux ropes with different degrees of coherency. The observation signifies the importance of internal structure and dynamics in understanding CMEs and in predicting their impacts on Earth.
A.K.A. and R.L. are supported by NSFC 41474151, 41774150, and 41761134088. A.K.A. acknowledges the International postdoctoral program of USTC. H.W. is supported by NSF AGS-1408703 and AGS-1620875. Y.W. acknowledges the support from NSFC 41774178 and 41574165. C.S. is supported by NSFC 41774181. This work is also supported by NSFC 41421063, CAS Key Research Program of Frontier Sciences QYZDB-SSW-DQC015, and the fundamental research funds for the central universities. Software: SolarSoftWare (Freeland & Handy 2012). |
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| 149. | Liu, Jiajia*, Yudong Ye, Chenglong Shen, Yuming Wang, and Robert Erdelyi, A New Tool for CME Arrival Time Prediction Using Machine Learning Algorithms: CAT-PUMA, Astrophys. J., 855, 109(10pp), 2018-03. [(983.2KB)] | Abstract. Coronal mass ejections (CMEs) are arguably the most violent eruptions in the solar system. CMEs can cause severe disturbances in interplanetary space and can even affect human activities in many aspects, causing damage to infrastructure and loss of revenue. Fast and accurate prediction of CME arrival time is vital to minimize the disruption that CMEs may cause when interacting with geospace. In this paper, we propose a new approach for partial-/full halo CME Arrival Time Prediction Using Machine learning Algorithms (CAT-PUMA). Via detailed analysis of the CME features and solar-wind parameters, we build a prediction engine taking advantage of 182 previously observed geo-effective partial-/full halo CMEs and using algorithms of the Support Vector Machine. We demonstrate that CAT-PUMA is accurate and fast. In particular, predictions made after applying CAT-PUMA to a test set unknown to the engine show a mean absolute prediction error of ∼5.9 hr within the CME arrival time, with 54% of the predictions having absolute errors less than 5.9 hr. Comparisons with other models reveal that CAT-PUMA has a more accurate prediction for 77% of the events investigated that can be carried out very quickly, i.e., within minutes of providing the necessary input parameters of a CME. A practical guide containing the CATPUMA engine and the source code of two examples are available in the Appendix, allowing the community to perform their own applications for prediction using CAT-PUMA.
The SOHO LASCO CME catalog is generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory. SOHO is a project of international cooperation between ESA and NASA. J.L. appreciates discussions with Dr. Xin Huang (National Astronomical Observatories, Chinese Academy of Sciences). We thank Dr. Manolis K. Georgoulis (Research Center for Astronomy and Applied Mathematics, Academy of Athens) for his useful advice in improving this paper. J.L. and R.E. acknowledge the support (grant number ST/M000826/1) received by the Science and Technology Facility Council (STFC), UK. R.E. is grateful for the support received from the Royal Society (UK). Y.W. is supported by grants 41574165 and 41774178 from NSFC. |
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| 148. | Zhuang, Bin, YuMing Wang, ChengLong Shen, and Rui Liu, A statistical study of the likelihood of a super geomagnetic storm occurring in a mild solar cycle, Earth and Planetary Physics, 2, 112-119, 2018-03. [(533.1KB)] | Abstract. The activities of geomagnetic storms are generally controlled by solar activities. The current solar cycle (SC) 24 is found to be mild; compared to SCs 19–23, the storm occurrence and size derived by averaging the occurrence number and Dst around the solar maximum are reduced by about 50–82% and 36–61%, respectively. We estimate separately, for SC 19 to 24, the repeat intervals between geomagnetic storms of specific Dst, based on fits of power-law and log-normal distributions to the storm data for each SC. Repeat intervals between super geomagnetic storms with Dst≤–250 nT are found to be 0.36–2.95 year(s) for SCs 19–23, but about 20 years based on the data for SC 24. We also estimate the repeat intervals between coronal mass ejections (CMEs) of specific speed (VCME) since CMEs are known to be the main drivers of intense storms and the related statistics may provide information about the potential occurrence of super geomagnetic storms from the location of the Sun. Our analysis finds that a CME with VCME≥1860 km/s may occur once per 3 and 5 months in SC 23 and 24, respectively. Based on a VCME-Dst relationship, such a fast CME may cause a storm with Dst=–250 nT if arriving at the Earth. By comparing the observed geomagnetic storms to storms expected to be caused by CMEs, we derive the probability of CME caused storms, which is dependent on VCME. For a CME faster than 1860 km/s, the probability of a CME caused storm with Dst≤–250 nT is about 1/5 for SC 23 or 1/25 for SC 24. All of the above results suggest that the likelihood of the occurrence of super geomagnetic storms is significantly reduced in a mild SC.
We acknowledge and thank the World Data Center for Geomagnetism (Kyoto) for use of the geomagnetic storm Dst database, and the Royal Observatory of Belgium (ROB) for use of sunspot number data. The CME catalog is generated and maintained at the CDAW Data Center by NASA and the Catholic University of America in cooperation with the Naval Research Laboratory. This work is supported by grants from NSFC (41774178, 41574165,
41421063, and 41274173), and the fundamental research funds for the central universities. |
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| 147. | Su, Zhenpeng, Nigang, Liu, Huinan Zheng, Yuming Wang, and Shui Wang, Large-amplitude extremely low frequency hiss waves in plasmaspheric plumes, Geophys. Res. Lett., 45, 565-577, 2018-02. [(8.43MB)] | |
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| 146. | Liu, Nigang, Su, Zhenpeng, Huinan Zheng, Yuming Wang, and Shui Wang, Prompt disappearance and emergence of radiation belt magnetosonic waves induced by solar wind dynamic pressure variations, Geophys. Res. Lett., 45, 585-594, 2018-02. [(5.06MB)] | |
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| 145. | Liu, Jiajia, Robert Erdelyi, Yuming Wang, and Rui Liu, Untwisting jets related to magnetic flux cancellation, Astrophys. J., 852, 10(12pp), 2018-01. [(3.42MB)] | Abstract. The rotational motion of solar jets is believed to be a signature of the untwisting process resulting from magnetic reconnection, which takes place between twisted closed magnetic loops (i.e., magnetic flux ropes) and open magnetic field lines. The identification of the pre-existing flux rope, and the relationship between the twist contained in the rope and the number of turns the jet experiences, are then vital in understanding the jet-triggering mechanism. In this paper, we will perform a detailed analysis of imaging, spectral, and magnetic field observations of four homologous jets, among which the fourth one releases a twist angle of 2.6π. Nonlinear force-free field extrapolation of the photospheric vector magnetic field before the jet eruption presents a magnetic configuration with a null point between twisted and open fields—a configuration highly in favor of the eruption of solar jets. The fact that the jet rotates in the opposite sense of handness to the twist contained in the pre-eruption photospheric magnetic field confirms the unwinding of the twist by the jet’s rotational motion. The temporal relationship between jets’ occurrence and the total negative flux at their source region, together with the enhanced magnetic submergence term of the photospheric Poynting flux, shows that these jets are highly associated with local magnetic flux cancellation.
We thank the referee for his thorough comments and suggestions. We acknowledge the use of observations from SDO and IRIS. Vector magnetic field data is courtesy of the HMI science team. We acknowledge the use of codes in the following papers: Welsch & Longcope (2003; YAFTA), Wiegelmann (2008; NLFFF), and Schuck (2008; DAVE4VM). J.L. also benefits from discussions with Dr. Etienne Pariat. J.L. and R.E. acknowledge the support received by the Science and Technology Facility Council (STFC), UK. R.E. is grateful for the support received from the Royal Society (UK). This work is also supported by the Anhui Provincial Natural Science Foundation, China. Y.W. is supported by the grants 41574165 and 41421063 from NSFC. R.L. is supported by grants 41774150 and 41474151 from NSFC. |
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| 144. | Wang, Haimin, Rui Liu, Qin Li, Chang Liu, Na Deng, Yan Xu, Ju Jing, Yuming Wang, and Wenda Cao, Extending Counter-Streaming Motion from an Active Region Filament to a Sunspot Light Bridge, Astrophys. J. Lett., 852, L18(6pp), 2018-01. [(6.76MB)] | Abstract. We analyze high-resolution observations from the 1.6 m telescope at Big Bear Solar Observatory that cover an active region filament. Counter-streaming motions are clearly observed in the filament. The northern end of the counter-streaming motions extends to a light bridge, forming a spectacular circulation pattern around a sunspot, with clockwise motion in the blue wing and counterclockwise motion in the red wing, as observed in the Hα offbands. The apparent speed of the flow is around 10–60 km s−1 in the filament, decreasing to 5–20 km s−1 in the light bridge. The most intriguing results are the magnetic structure and the counter-streaming motions in the light bridge. Similar to those in the filament, the magnetic fields show a dominant transverse component in the light bridge. However, the filament is located between opposed magnetic polarities, while the light bridge is between strong fields of the same polarity. We analyze the power of oscillations with the image sequences of constructed Dopplergrams, and find that the filament’s counter-streaming motion is due to physical mass motion along fibrils, while the light bridge’s counter-streaming motion is due to oscillation in the direction along the line-of-sight. The oscillation power peaks around 4 minutes. However, the section of the light bridge next to the filament also contains a component of the extension of the filament in combination with the oscillation, indicating that some strands of the filament are extended to and rooted in that part of the light bridge.
We are grateful to the referee for the very helpful comments that improved the Letter. We acknowledge the BBSO and SDO teams for providing the data. This work is supported by NSF under grants AGS 1348513, 1408703, and 1539791. R. Liu acknowledges NSFC 41474151 and 41774150 grants. H.W. acknowledges the International Visiting Professor Program of USTC. |
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| 2017 Top |
| 143. | Zhou, Zhenjun, Jie Zhang, Yuming Wang, Rui Liu, and Georgios Chintzoglou, Toward Understanding the 3-D Structure and Evolution of Magnetic Flux Rope in an Extremely-Long-Duration Eruptive Flare, Astrophys. J., 851, 133(12pp), 2017-12. [(5.48MB)] | | Abstract. In this work, we analyze the initial eruptive process of an extremely long duration C7.7-class flare that occurred on 2011 June 21. The flare had a 2 hr long rise time in soft X-ray emission, which is much longer than the rise time of most solar flares, including both impulsive and gradual ones. Combining the facts that the flare occurred near the disk center as seen by the Solar Dynamic Observatory (SDO) but near the limb as seen by two Solar Terrestrial Relations Observatory (STEREO) spacecraft, we are able to track the evolution of the eruption in 3D in a rare slow-motion manner. The time sequence of the observed large-scale EUV hot channel structure in the Atmospheric Imaging Assembly (AIA) high-temperature passbands of 94 and 131 Å clearly shows the process of how the sigmoid structure prior to the eruption was transformed into a near-potential post-eruption loop arcade. We believe that the observed sigmoid represents the structure of a twisted magnetic flux rope (MFR), which has reached a height of about 60 Mm at the onset of the eruption. We argue that the onset of the flare precursor phase is likely triggered by the loss of the magnetohydrodynamic equilibrium of a preexisting MFR, which leads to the slow rise of the flux rope. The rising motion of the flux rope leads to the formation of a vertical current sheet underneath, triggering the fast magnetic reconnection that in turn leads to the main phase of the flare and fast acceleration of the flux rope. |
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| 142. | Zhang, Quanhao, Yuming Wang, Youqiu Hu, Rui Liu, Kai Liu, and Jiajia Liu, Upward and downward catastrophes of coronal magnetic flux ropes in quadrupolar magnetic fields, Astrophys. J., 851, 96(12pp), 2017-12. [(962.9KB)] | | Abstract. Coronal magnetic flux ropes are closely related to large-scale solar activities. Using a 2.5-dimensional time-dependent ideal magnetohydrodynamic model in Cartesian coordinates, we carry out numerical simulations to investigate the evolution of a magnetic system consisting of a flux rope embedded in a fully closed quadrupolar magnetic field with different photospheric flux distributions. It is found that when the photospheric flux is not concentrated too much toward the polarity inversion line and the constraint exerted by the background field is not too weak, the equilibrium states of the system are divided into two branches: the rope sticks to the photosphere for the lower branch and levitates in the corona for the upper branch. These two branches are connected by an upward catastrophe (from the lower branch to the upper) and a downward catastrophe (from the upper branch to the lower). Our simulations reveal that there exist both upward and downward catastrophes in quadrupolar fields, which may be either force-free or non-force-free. The existence and the properties of these two catastrophes are influenced by the photospheric flux distribution, and a downward catastrophe is always paired with an upward catastrophe. Comparing the decay indices in catastrophic and noncatastrophic cases, we infer that torus unstable may be a necessary but not sufficient condition for a catastrophic system. |
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| 141. | Wang, Wensi, Rui Liu*, Yuming Wang, Qiang Hu, Chenglong Shen, Chaowei Jiang, and Chunming Zhu, Buildup of a Highly Twisted Magnetic Flux Rope during a Solar Eruption, Nat. Comm., 8, 1330, 2017-11. [(8.99MB)] | | Abstract. The magnetic flux rope is among the most fundamental magnetic configurations in plasma. Although its presence after solar eruptions has been verified by spacecraft measurements near Earth, its formation on the Sun remains elusive, yet is critical to understanding a broad spectrum of phenomena. Here we study the dynamic formation of a magnetic flux rope during a classic two-ribbon flare. Its feet are identified unambiguously with conjugate coronal dimmings completely enclosed by irregular bright rings, which originate and expand outward from the far ends of flare ribbons. The expansion is associated with the rapid ribbon separation during the flare main phase. Counting magnetic flux through the feet and the ribbon-swept area reveals that the rope’s core is more twisted than its average of four turns. It propagates to the Earth as a typical magnetic cloud possessing a similar twist profile obtained by the Grad-Shafranov reconstruction of its three dimensional structure. |
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| 140. | Wang, Yuming and Rui Liu, Existing an Upper Limit in the Magnetic Energy of a Stable Magnetic Flux Rope?, Res. Notes AAS, 1, 10, 2017-11. [(75.5KB)] | |
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| 139. | Su Zhenpeng, H. E. Spence, Zhonglei Gao, G. D. Reeves, Huinan Zheng, D. N. Baker, Yuming Wang, Shui Wang, and J. R. Wygant, Rapid Loss of Radiation Belt Relativistic Electrons by EMIC Waves, J. Geophys. Res. - Space Phys., 122, 2017-10. [(36.81MB)] | |
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| 138. | Liu, Nigang, Zhenpeng Su, Zhonglei Gao, G. D. Reeves, Huinan Zheng, Yuming Wang, and Shui Wang, Shock-Induced Disappearance and Subsequent Recovery of Plasmaspheric Hiss: Coordinated Observations of RBSP, THEMIS, and POES Satellites, J. Geophys. Res. - Space Phys., 122, 2017-10. [(12.02MB)] | |
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| 137. | Shen, Fang, Yuming Wang, Chenglong Shen, and Xueshang Feng, On the Collision Nature of Two Coronal Mass Ejections: A Review, Sol. Phys., 292, 104(20pp), 2017-08. [(1.18MB)] | Abstract. Observational and numerical studies have shown that the kinematic characteristics of two or more coronal mass ejections (CMEs) may change significantly after a CME collision. The collision of CMEs can have a different nature, i.e. inelastic, elastic, and superelastic processes, depending on their initial kinematic characteristics. In this article, we first review the existing definitions of collision types including Newton’s classical definition, the energy definition, Poisson’s definition, and Stronge’s definition, of which the first two were used in the studies of CME–CME collisions. Then, we review the recent research progresses on the nature of CME–CME collisions with the focus on which CME kinematic properties affect the collision nature. It is shown that observational analysis and numerical simulations can both yield an inelastic, perfectly inelastic, merging-like collision, or a high possibility of a superelastic collision. Meanwhile, previous studies based on a 3D collision picture suggested that a low approaching speed of two CMEs is favorable for a superelastic nature. Since CMEs are an expanding magnetized plasma structure, the CME collision process is quite complex, and we discuss this complexity. Moreover, the models used in both observational and numerical studies contain many limitations. All of the previous studies on collisions have not shown the separation of two colliding CMEs after a collision. Therefore the collision between CMEs cannot be considered as an ideal process in the context of a classical Newtonian definition. In addition, many factors are not considered in either observational analysis or numerical studies, e.g. CME-driven shocks and magnetic reconnections. Owing to the complexity of the CME collision process, a more detailed and in-depth observational analysis and simulation work are needed to fully understand the CME collision process.
We acknowledge the constructive discussion with Chuanyi Tu from Peking University, who pointed out the difference between the classic Newtonian definition of a collision and the energy definition for colliding objects with a changing expanding speed, and the weaknesses and limitations in the analysis of the collision nature. F. Shen appreciates the discussion with Jiansen He from Peking University and Xin Wang from Beihang University. We are also grateful to the referee and the Guest Editor for improving the quality of the manuscript. F.S and X.F are supported by the grants from NSFC No. 41474152 and 41531073, Y.W and C.S are supported by the grants from NSFC No. 41574165, 41131065, 41274173, and 41421063. This work is also supported by the grants from the Specialized Research Fund for State Key Laboratories, and the National Program for Support of Top-notch Young Professionals. Some of the figures in this article have been published by permission of the AAS as indicated in the text. |
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| 136. | Zhuang, Bin, Yuming Wang*, Chenglong Shen, Siqing Liu, Jingjing Wang, Zonghao Pan, Huimin Li, and Rui Liu, The significance of the influence of the CME deflection in interplanetary space on the CME arrival at the Earth, Astrophys. J., 845, 117(12pp), 2017-08. [(2.12MB)] | Abstract. As one of the most violent astrophysical phenomena, coronal mass ejections (CMEs) have strong potential space weather effects. However, not all Earth-directed CMEs encounter the Earth and produce geo-effects. One reason is the deflected propagation of CMEs in interplanetary space. Although there have been several case studies clearly showing such deflections, it has not yet been statistically assessed how significantly the deflected propagation would influence the CME’s arrival at Earth. We develop an integrated CME-arrival forecasting (iCAF) system, assembling the modules of CME detection, three-dimensional (3D) parameter derivation, and trajectory reconstruction to predict whether or not a CME arrives at Earth, and we assess the deflection influence on the CME-arrival forecasting. The performance of iCAF is tested by comparing the two-dimensional (2D) parameters with those in the Coordinated Data Analysis Workshop (CDAW) Data Center catalog, comparing the 3D parameters with those of the gradual cylindrical shell model, and estimating the success rate of the CME Eartharrival predictions. It is found that the 2D parameters provided by iCAF and the CDAW catalog are consistent with each other, and the 3D parameters derived by the ice cream cone model based on single-view observations are acceptable. The success rate of the CME-arrival predictions by iCAF with deflection considered is about 82%, which is 19% higher than that without deflection, indicating the importance of the CME deflection for providing a reliable forecasting. Furthermore, iCAF is a worthwhile project since it is a completely automatic system with deflection taken into account.
We acknowledge the use of the data from the SOHO spacecraft and the use of the CME catalog. SOHO is a mission of international cooperation between ESA and NASA. The CME catalog is generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory. We also acknowledge the test of iCAF that took place at the Space Environment Prediction Center of the National Space Science Center, Chinese Academy of Sciences. This work is supported
by grants from NSFC (41574165, 41421063, 41274173, and 41474151), and fundamental research funds for the central universities. |
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| 135. | Liu, Lijuan*, Yuming Wang*, Rui Liu, Zhenjun Zhou, M. Temmer, J. K. Thalmann, Jiajia Liu, Kai Liu, Chenglong Shen, Quanhao Zhang, and A. M. Veronig, The causes of quasi-homologous CMEs, Astrophys. J., 844, 141(19pp), 2017-08. [(7.02MB)] | Abstract. In this paper, we identified the magnetic source locations of 142 quasi-homologous (QH) coronal mass ejections (CMEs), of which 121 are from solar cycle (SC) 23 and 21 from SC 24. Among those CMEs, 63% originated from the same source location as their predecessor (defined as S-type), while 37% originated from a different location within the same active region as their predecessor (defined as D-type). Their distinctly different waiting time distributions, peaking around 7.5 and 1.5hr for S- and D-type CMEs, suggest that they might involve different physical mechanisms with different characteristic timescales. Through detailed analysis based on nonlinear forcefree coronal magnetic field modeling of two exemplary cases, we propose that the S-type QH CMES might involve a recurring energy release process from the same source location (by magnetic free energy replenishment), whereas the D-type QH CMEs can happen when a flux tube system is disturbed by a nearby CME.
We thank our anonymous referee for his/her constructive comments that significantly improved the manuscript. We acknowledge the use of the data from HMI and AIA instruments on board Solar Dynamics Observatory (SDO); EIT, MDI, and LASCO instruments on board Solar and Heliospheric Observatory (SOHO); and Transition Region and Coronal Explorer (TRACE). This work is supported by the grants from NSFC (41574165, 41421063, 41274173, 41474151, 41131065), CAS (Key Research Program KZZDEW-01-4), MOEC (20113402110001), and the fundamental research funds for the central universities. |
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| 134. | Su, Zhenpeng, Geng Wang, Nigang Liu, Huinan Zheng, Yuming Wang, and Shui Wang, Direct observation of generation and propagation of magnetosonic waves following substorm injection, Geophys. Res. Lett., 44, 7587-7597, 2017-08. [(7.98MB)] | |
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| 133. | Zhao, Ake, Yuming Wang*, Jiajia Liu, Zhenjun Zhou, Chenglong Shen, Rui Liu, Bin Zhuang, and Quanhao Zhang, The role of viscosity in causing the plasma poloidal motion in magnetic clouds, Astrophys. J., 845, 109(6pp), 2017-08. [(573.7KB)] | Abstract. An interesting phenomenon, plasma poloidal motion, has been found in many magnetic clouds (MCs), and viscosity has been proposed as a possible mechanism. However, it is not clear how significant the role of viscosity is in generating such motion. In this paper, we conduct a statistical study of the MCs detected by the Wind spacecraft during 1995–2012. It is found that, for 19% of all the studied MCs (186), the poloidal velocities of the MC plasma near the MC boundaries are well correlated with those of the corresponding ambient solar wind plasma. A non-monotonic increase from inner to outer MCs suggests that the viscosity does play a role, albeit weak, on the poloidal motion in the MC statistically. The possible dependence on the solar wind parameters is then studied in detail for the nine selected crossings, which represent the viscosity characteristic. There is an evident negative correlation between the viscosity and the density, a weak negative correlation between the viscosity and the turbulence strength, and no clear correlation between the viscosity and the temperature.
We acknowledge that we use the data from the Wind spacecraft. This research is supported by NSFC (41574165, 41421063, 41131065), Key Research Program of Frontier Sciences (CAS QYZDB-SSW-DQC015), and the fundamental research funds for the central universities WK2080000077. |
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| 132. | Mishra, Wageesh, Yuming Wang, Nandita Srivastava, and Chenglong Shen, Assessing the Nature of Collisions of Coronal Mass Ejections in the Inner Heliosphere, Astrophys. J. Supp., 232, 5(24pp), 2017-08. [(7.71MB)] | Abstract. There have been several attempts in the past to understand the nature of the collision of individual cases of interacting coronal mass ejections (CMEs). We selected eight cases of interacting CMEs and estimated their propagation and expansion speeds, and direction of impact and masses, by exploiting coronagraphic and heliospheric imaging observations. Using these estimates while ignoring the errors therein, we find that the nature of collisions is perfectly inelastic for two cases (i.e., 2012 March and November), inelastic for two cases (i.e., 2012 June and 2011 August), elastic for one case (i.e., 2013 October), and super-elastic for three cases (i.e., 2011 February, 2010 May, and 2012 September). Including the large uncertainties in the estimated directions, angular widths, and pre-collision speeds, the probability of a perfectly inelastic collision for the 2012 March and November cases drops from 98% to 60% and 100% to 40%, respectively, increasing the probability for other types of collision. Similarly, the probability of an inelastic collision drops from 95% to 50% for the 2012 June case, 85% to 50% for the 2011 August case, and 75% to 15% for the 2013 October case. We note that the probability of a superelastic collision for the 2011 February, 2010 May, and 2012 September CMEs drops from 90% to 75%, 60% to 45%, and 90% to 50%, respectively. Although the sample size is small, we find good dependence of the nature of collision on the CME parameters. The crucial pre-collision parameters of the CMEs responsible for increasing the probability of a super-elastic collision are, in descending order of priority, their lower approaching speed, expansion speed of the following CME higher than the preceding one, and a longer duration of the collision phase.
We acknowledge the UK Solar System Data Center for providing the processed Level-2 STEREO/HI data. This work is supported by NSFC grant Nos. 41131065, 41574165, and 41421063. W.M. is supported by the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) grant No. 2015PE015. We thank the referee for insightful comments. W.M. also thanks A. K. Awasthi and A. Raghav for helpful discussions. |
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| 131. | Wang, Dong, Rui Liu, Yuming Wang, Kai Liu, Jun Chen, Jiajia Liu, Zhenjun Zhou, and Min Zhang, Critical Height of the Torus Instability in Two-Ribbon Solar Flares, Astrophys. J. Lett., 843, L9(6pp), doi:10.3847/2041-8213/aa79f0, 2017-07. [(965.7KB)] | Abstract. We studied the background field for 60 two-ribbon flares of M-and-above classes during 2011–2015. These flares are categorized into two groups, i.e., eruptive and confined flares, based on whether a flare is associated with a coronal mass ejection or not. The background field of source active regions is approximated by a potential field extrapolated from the Bz component of vector magnetograms provided by the Helioseismic and Magnetic Imager. We calculated the decay index n of the background field above the flaring polarity inversion line, and defined a critical height hcrit corresponding to the theoretical threshold (ncrit = 1.5) of the torus instability. We found that hcrit is approximately half of the distance between the centroids of opposite polarities in active regions and that the distribution of hcrit is bimodal: it is significantly higher for confined flares than for eruptive ones. The decay index increases monotonously with increasing height for 86% (84%) of the eruptive (confined) flares but displays a saddle-like profile for the rest, 14% (16%), which are found exclusively in active regions of multipolar field configuration. Moreover, n at the saddle bottom is significantly smaller in confined flares than that in eruptive ones. These results highlight the critical role of background field in regulating the eruptive behavior of two-ribbon flares.
The authors thank the anonymous reviewer for constructive comments that helped greatly improve this Letter. D.W. acknowledges the support by Natural Science Foundation of Anhui province education department (KJ2016JD18, KJ2017A493). R.L. acknowledges the support by NSFC 41474151 and the Thousand Young Talents Program of China, and thanks T. Török for helpful comments. Y.W. acknowledges the support from NSFC 41131065 and 41574165. This work was also supported by NSFC 41421063, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. |
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| 130. | Shen, Chenglong, Yutian Chi, Yuming Wang, Mengjiao Xu, and Shui Wang, Statistical Comparison of the ICME's Geoeffectiveness of Different Types and Different Solar Phases from 1995 to 2014, J. Geophys. Res. - Space Phys., 122, 5931-5948, 2017-06. [(5.75MB)] | Abstract. The geoeffectiveness of interplanetary coronal mass ejections (ICMEs) is an important issue in space weather research and forecasting. Based on the ICME catalog that we recently established and the Dst indices from the World Data Center, we study and compare the geoeffectiveness of ICMEs of different in situ signatures and different solar phases from 1995 to 2014. According to different in situ signatures, all ICMEs are divided into three types: isolated ICMEs (I-ICMEs), multiple ICMEs (M-ICMEs), and shock-embedded ICMEs (S-ICMEs), resulting in a total of 363 group events. The main findings of this work are as follows: (1) Fifty-eight percent of ICMEs caused geomagnetic storms with Dst min ≤ −30 nT. Further, large fraction (87%) of intense geomagnetic storms are caused by ICME groups and their sheath regions. (2) Numbers of ICME groups and the probabilities of ICME groups in causing geomagnetic storms varied in pace with the solar cycle. Meanwhile, the ICME groups and the probabilities of them in causing geomagnetic storms in Solar Cycle 24 are much lower than those in Solar Cycle 23. (3) The maximum value of the intensity of the magnetic field ( B ), south component of the magnetic field ( B s ), and dawn-dusk electric field vB s are well correlated with the intensity of the magnetic storms. (4) Shock-embedded ICMEs have a high probability in causing geomagnetic storms, especially intense geomagnetic storms. (5) The compression of shock on the south component of magnetic field is an important factor to enhance the geoeffectiveness of S-ICMEs structures.
We acknowledge the use of the data from Wind and ACE satellites and the world data center (WDC). for Geomagnetism, Kyoto. The Wind/MFI, Wind/SWE, Wind/SFPD, and Wind/3DP data are downloaded from the NASA’s Space Physics Data Facility (SPDF, http://spdf.gsfc.nasa.gov/). The suprathermal electron pitch angle distribution data from ACE are gotten from http://www.srl.caltech.edu/ ACE/ASC/DATA/level3/swepam/data/. The Dst indices came from the link of http://wdc.kugi.kyoto-u.ac.jp/. The yearly sunspot number data locate at Royal Observatory of Belgium via the link http://www.sidc.be/silso/datafiles. This work is supported by grants from MOST 973 Key Project (2011CB811403), CAS (Key Research Program KZZD-EW-01, 100-Talent Program, Youth Innovation Promotion Association CAS and Key Research Program of Frontier Sciences QYZDB-SSW-DQC015), NSFC (41131065, 41121003, 41274173, 41222031, and 41404134), the Fundamental Research Funds for the Central Universities and the Specialized Research Fund for State Key Laboratories. |
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| 129. | Gao, Zhonglei, Zhenpeng Su, Lunjin Chen, Huinan Zheng, Yuming Wang, and Shui Wang, Van Allen Probes observations of whistler-mode chorus with long-lived oscillating tones, Geophys. Res. Lett., 44, 5909-5919, 2017-06. [(10.16MB)] | |
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| 128. | Yang, Chang, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, YumingWang, Shui Wang, H. E. Spence, G. D. Reeves, D. N. Baker, J. B. Blake, G. D. Reeves, and H. O. Funsten, A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region, Geophys. Res. Lett., 44, 3980-3990, 2017-05. [(4.16MB)] | |
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| 127. | Michael W. Liemohn, Yuming Wang, Alan Rodger, Larry Kepko, and Michael Balikhin, Editorial: Thanking the JGR Space Physics reviewers of 2016, J. Geophys. Res. - Space Phys., 122, 5528-5538, 2017-05. [(132.4KB)] | |
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| 126. | Lugaz, Noe, Manuela Temmer, Yuming Wang, and Charlie Farrugia, The Interaction of Successive Coronal Mass Ejections: A Review, Sol. Phys., 292, 64(37pp), 2017-04. [(7.22MB)] | Abstract. We present a review of the different aspects associated with the interaction of successive coronal mass ejections (CMEs) in the corona and inner heliosphere, focusing on the initiation of series of CMEs, their interaction in the heliosphere, the particle acceleration associated with successive CMEs, and the effect of compound events on Earth’s magnetosphere. The two main mechanisms resulting in the eruption of series of CMEs are sympathetic eruptions, when one eruption triggers another, and homologous eruptions, when a series of similar eruptions originates from one active region. CME–CME interaction may also be associated with two unrelated eruptions. The interaction of successive CMEs has been observed remotely in coronagraphs (with the Large Angle and Spectrometric Coronagraph Experiment – LASCO – since the early 2000s) and heliospheric imagers (since the late 2000s), and inferred from in situ measurements, starting with early measurements in the 1970s. The interaction of two or more CMEs is associated with complex phenomena, including magnetic reconnection, momentum exchange, the propagation of a fast magnetosonic shock through a magnetic ejecta, and changes in the CME expansion. The presence of a preceding CME a few hours before a fast eruption has been found to be connected with higher fluxes of solar energetic particles (SEPs), while CME–CME interaction occurring in the corona is often associated with unusual radio bursts, indicating electron acceleration. Higher suprathermal population, enhanced turbulence and wave activity, stronger shocks, and shock – shock or shock –CME interaction have been proposed as potential physical mechanisms to explain the observed associated SEP events. When measured in situ, CME– CME interaction may be associated with relatively well organized multiplemagnetic cloud events, instances of shocks propagating through a previous magnetic ejecta or more complex ejecta, when the characteristics of the individual eruptions cannot be easily distinguished. CME– CME interaction is associated with some of the most intense recorded geomagnetic storms. The compression of a CME by another and the propagation of a shock inside a magnetic ejecta can lead to extreme values of the southward magnetic field component, sometimes associated with high values of the dynamic pressure. This can result in intense geomagnetic storms, but can also trigger substorms and large earthward motions of the magnetopause, potentially associated with changes in the outer radiation belts. Future in situ measurements in the inner heliosphere by Solar Probe+ and Solar Orbiter may shed light on the evolution of CMEs as they interact, by providing opportunities for conjunction and evolutionary studies.
Acknowledgements We acknowledge the following grants: NASA grant NNX15AB87G and NSF grants AGS1435785, AGS1433213 and AGS1460179 (N. Lugaz), NSFC grants 41131065 and 41574165 (Y.Wang), Austrian Science Fund FWF: V195-N16 (M. Temmer), and NASA grant NNX16AO04G (C.J. Farrugia). N. Lugaz would like to acknowledge W.B. Manchester, I.I. Roussev, Y.D. Liu, G. Li, J.A. Davies, T.A. Howard, and N.A. Schwadron for fruitful discussion about CME–CME interaction over the years, as well as the VarSITI program. Some of the figures in this article have been published by permission of the AAS and John Wiley and Sons, as indicated in the text. |
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| 125. | Zhao, Ake*, Yuming Wang*, Yutian Chi, Jiajia Liu, Chenglong Shen, and Rui Liu, Main cause of the poloidal plasma motion inside a magnetic cloud inferred from multiple-spacecraft observations, Sol. Phys., 292, 58, doi:10.1007/s11207-017-1077-4, 2017-03. [(1.21MB)] | Abstract. Although the dynamical evolution of magnetic clouds (MCs) has been one of the foci of interplanetary physics for decades, only few studies focus on the internal properties of large-scale MCs. Recent work by Wang et al. (J. Geophys. Res. 120, 1543, 2015) suggested the existence of the poloidal plasma motion inMCs. However, the main cause of this motion is not clear. In order to find it, we identify and reconstruct the MC observed by the Solar Terrestrial Relations Observatory (STEREO)-A, Wind, and STEREO-B spacecraft during 19 – 20 November 2007 with the aid of the velocity-modified cylindrical force-free flux rope model. We analyze the plasma velocity in the plane perpendicular to the MC axis. It is found that there was evident poloidal motion at Wind and STEREO-B, but this was not clear at STEREO-A, which suggests a local cause rather than a global cause for the poloidal plasma motion inside the MC. The rotational directions of the solar wind and MC plasma at the two sides of the MC boundary are found to be consistent, and the values of the rotational speeds of the solar wind and MC plasma at the three spacecraft show a rough correlation. All of these results illustrate that the interaction with ambient solar wind through viscosity might be one of the local causes of the poloidal motion. Additionally, we propose another possible local cause: the existence of a pressure gradient in the MC. The significant difference in the total pressure at the three spacecraft suggests that this speculation is perhaps correct.
We acknowledge use of data from STEREO, ACE, and Wind. This research is supported by NSFC (41131065, 41574165, 41421063, 41274173, 41222031), CAS (Key Research Program KZZD-EW-01 and 100-Talent Program), and the fundamental research funds for the central universities. |
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| 124. | Zhang, Quanhao, Yuming Wang, Youqiu Hu, Rui Liu, and Jiajia Liu, Influence of Photospheric Magnetic Conditions on the Catastrophic Behaviors of Flux Ropes in Active Regions, Astrophys. J., 835, 211(10pp), 2017-02. [(505.4KB)] | Abstract. Since only the magnetic conditions at the photosphere can be routinely observed in current observations, it is of great significance to determine the influences of photospheric magnetic conditions on solar eruptive activities. Previous studies about catastrophe indicated that the magnetic system consisting of a flux rope in a partially open bipolar field is subject to catastrophe, but not if the bipolar field is completely closed under the same specified photospheric conditions. In order to investigate the influence of the photospheric magnetic conditions on the catastrophic behavior of this system, we expand upon the 2.5-dimensional ideal magnetohydrodynamic model in Cartesian coordinates to simulate the evolution of the equilibrium states of the system under different photospheric flux distributions. Our simulation results reveal that a catastrophe occurs only when the photospheric flux is not concentrated too much toward the polarity inversion line and the source regions of the bipolar field are not too weak; otherwise no catastrophe occurs. As a result, under certain photospheric conditions, a catastrophe could take place in a completely closed configuration, whereas it ceases to exist in a partially open configuration. This indicates that whether the background field is completely closed or partially open is not the only necessary condition for the existence of catastrophe, and that the photospheric conditions also play a crucial role in the catastrophic behavior of the flux rope system.
This research is supported by Grants from NSFC 41131065, 41574165, 41421063, 41474151, and 41222031, MOEC 20113402110001, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities WK2080000077. R.L. acknowledges the support from the Thousand Young Talents Program of China. |
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| 123. | Wang, Geng, Zhenpeng Su, Huinan Zheng, Yuming Wang, Min Zhang, and Shui Wang, Nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultra-relativistic electrons by oblique monochromatic EMIC waves, J. Geophys. Res. - Space Phys., 122, 1928-1945, 2017-02. [(12.13MB)] | |
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| 122. | Wang, Wensi, Rui Liu*, and Yuming Wang, Tornado-Like Evolution of A Kink-Unstable Solar Prominence, Astrophys. J., 834, 38(11pp), 2017-01. [(11.89MB)] | Abstract. We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ∼150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe IX 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.
We thank B.Kliem for helpful comments, and the anonymous referee for constructive suggestions. R.L. acknowledges the support from the Thousand Young Talents Program of China and NSFC 41474151. Y.W. acknowledges the support from NSFC 41131065 and 41574165. This work was also supported by NSFC 41421063, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. |
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| 121. | Liu, Nigang, Su, Zhenpeng, Gao, Zhonglei, Zheng, Huinan, Wang, Yuming, Wang, Shui, Spence, H. E., Reeves, G. D., Baker, D. N., Blake, J. B., Funsten, H. O., and Wygant, J. R., Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure, Geophys. Res. Lett., 44, 52-61, 2017-01. | |
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| 120. | Liu, Jiajia, Yuming Wang, Robertus Erdelyi, Rui Liu, Scott W. McIntosh, Tingyu Gou, Jun Chen, Kai Liu, Lijuan Liu, and Zonghao Pan, On the Magnetic and Energy Characteristics of Recurrent Homologous Jets from An Emerging Flux, Astrophys. J., 833, 150(11pp), 2016-12. [(2.75MB)] | Abstract. In this paper, we present the detailed analysis of recurrent homologous jets originating from an emerging negative magnetic flux at the edge of an active region. The observed jets show multithermal features. Their evolution shows high consistence with the characteristic parameters of the emerging flux, suggesting that with more free magnetic energy, the eruptions tend to be more violent, frequent, and blowout-like. The average temperature, average electron number density, and axial speed are found to be similar for different jets, indicating that they should have been formed by plasmas from similar origins. Statistical analysis of the jets and their footpoint region conditions reveals a strong positive relationship between the footpoint region total 131 Å intensity enhancement and jets’ length/width. Stronger linearly positive relationships also exist between the total intensity enhancement/thermal energy of the footpoint regions and jets’ mass/kinetic/thermal energy, with higher cross-correlation coefficients. All the above results together confirm the direct relationship between the magnetic reconnection and the jets and validate the important role of magnetic reconnection in transporting large amounts of free magnetic energy into jets. It is also suggested that there should be more free energy released during the magnetic reconnection of blowout than of standard jet events.
We acknowledge the use of data from the AIA and HMI instruments on board Solar Dynamics Observatory (SDO). SDO is a mission for NASA’s Living With a Star (LWS) program. We thank T. Wiegelmann for the NLFFF extrapolation codes and I. G. Hannah and E. P. Kontar for the DEM codes. J.L. acknowledges support from the China Postdoctoral Science Foundation (2015M580540). This work is also supported by grants from the Fundamental Research Funds for the Central Universities, CAS (Key Research Program KZZD-EW-01-4), NSFC (41131065), and MOEC (20113402110001). R.E. acknowledges the support received by the Chinese Academy of Sciences President’s International Fellowship Initiative, grant no. 2016VMA045, the Science and Technology Facility Council (STFC), UK and the Royal Society (UK). R.L. acknowledges the support from the Thousand Young Talents Program of China and NSFC 41474151. |
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| 119. | Zhang, Quanhao*, Yuming Wang*, Rui Liu, Chenglong Shen, Min Zhang, Tingyu Gou, Jiajia Liu, Kai Liu, Zhenjun Zhou, and Shui Wang, Damped large amplitude oscillations in a solar prominence and a bundle of coronal loops, Res. Astron. Astrophys., 16, 167(10pp), 2016-11. [(20.77MB)] | Abstract. We investigate the evolutions of two prominences (P1, P2) and two bundles of coronal loops (L1, L2), observed with SDO/AIA near the east solar limb on 2012 September 22. It is found that there were large-amplitude oscillations in P1 and L1 but no detectable motions in P2 and L2. These transverse oscillations were triggered by a large-scale coronal wave, originating from a large flare in a remote active region behind the solar limb. By carefully comparing the locations and heights of these oscillating and non-oscillating structures, we conclude that the propagating height of the wave is between 50 Mm and 130 Mm. The wave energy deposited in the oscillating prominence and coronal loops is at least of the order of 10^28 erg. Furthermore, local magnetic field strength and Alfv´en speeds are derived from the oscillating periods and damping time scales, which are extracted from the time series of the oscillations. It is demonstrated that oscillations can be used in not only coronal seismology, but also to reveal the properties of the wave.
Acknowledgements. This research is supported by the National Natural Science Foundation of China (Grant Nos. 41131065, 41574165, 41421063 and 41304134), MOEC (20113402110001), CAS Key Research Program (KZZD-EW-01-4), the fundamental research funds for the central universities (WK2080000077), and the foundation for Young Talents in College of Anhui Province (2013SQRL044ZD). The CME catalog used to obtain the kinetic parameters of the relevant CME is generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory. SOHO is a project of international cooperation between ESA and NASA. |
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| 118. | Mishra, Wageesh*, Yuming Wang*, and Nandita Srivastava, On Understanding the Nature of Collisions of Coronal Mass Ejections Observed by STEREO, Astrophys. J., 831, 99(13pp), 2016-11. [(2.7MB)] | Abstract. We attempt to understand the collision characteristics of two coronal mass ejections (CMEs) launched successively from the Sun on 2013 October 25. The estimated kinematics, from three-dimensional (3D) reconstruction techniques applied to observations of CMEs by the SECCHI/Coronagraphic (COR) and Heliospheric Imagers, reveal their collision around 37 R☉ from the Sun. In the analysis, we take into account the propagation and expansion speeds, impact direction, and angular size as well as the masses of the CMEs. These parameters are derived from imaging observations, but may suffer from large uncertainties. Therefore, by adopting head-on as well as oblique collision scenarios, we have quantified the range of uncertainties involved in the calculation of the coefficient of restitution for expanding magnetized plasmoids. We show that the large expansion speed of the following CME compared with that of the preceding CME results in a higher probability of super-elastic collision. We also infer that a relative approaching speed of the CMEs lower than the sum of their expansion speeds increases the chance of a super-elastic collision. The analysis under reasonable errors in the observed parameters of the CME reveals a larger probability of occurrence of an inelastic collision for the selected CMEs. We suggest that the collision nature of two CMEs should be discussed in 3D, and the calculated value of the coefficient of restitution may suffer from a large uncertainty.
We acknowledge the UK Solar System Data Center for providing the processed Level-2 STEREO/HI data. The work is supported by the NSFC grant Nos. 41131065, 41574165, and 41421063. We also thank the reviewer whose comments have greatly improved this paper. W.M. is supported by the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) grant No. 2015PE015. |
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| 117. | Chi, Yutian, Chenglong Shen*, Yuming Wang, Mengjiao Xu, Pinzhong Ye, and Shui Wang, Statistical study of the interplanetary coronal mass ejections from 1995 to 2015, Sol. Phys., 291, 2419-2439, 2016-10. [(6.39MB)] | Abstract. We establish a catalog of interplanetary coronal mass ejections (ICMEs) during the period from 1995 to 2015 using the in-situ observations from the Wind and ACE spacecraft. Based on this catalog, we extend the statistical properties of ICMEs to the maximum phase of Solar Cycle 24.We confirm previous results that the yearly occurrence frequencies of ICMEs and shocks, the ratios of ICMEs driving shocks are correlated with the sunspot numbers. For the magnetic cloud (MC), we confirm that the yearly occurrence frequencies of MCs do not show any correlation with sunspot numbers. The highest MC ratio of ICME occurred near the solar minimum. In addition, we analyzed the yearly variation of the ICME parameters. We found that the ICME velocities, the magnetic-field strength, and their related parameters are varied in pace with solar-cycle variation. At the solar maximum, ICMEs move faster and carry a stronger magnetic field. By comparing the parameters between MCs and non-MC ejecta, we confirm the result that the magnetic-field intensities of MC are higher than those in non-MC ejecta. Furthermore, we also discuss the forward shocks driven by ICMEs. We find that one half of the ICMEs have upstream shocks and ICMEs with shocks have faster speed and higher magnetic-field strength than the ICMEs without shocks. The magnetic-field parameters and solar-wind plasma parameters in the shock sheath regions are higher than those in the ejecta regions of ICMEs from a statistical point of view.
We acknowledge the use of the data from Wind and ACE spacecraft. We also thank the Harvard-Smithsonian Center for Astrophysics Interplanetary Shock Database (supported by NASA grant number NNX13AI75G) for using their shock parameters. We thank the anonymous referee for the constructive comments. This work is supported by grants from MOST 973 key project (2011CB811403), CAS (Key Research Program KZZD-EW-01 and 100-Talent Program), NSFC (41131065, 41121003, 41274173, 41222031 and 41404134), the fundamental research funds for the central universities and the Specialized Research Fund for State Key Laboratories. |
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| 116. | Wang, Yuming*, Bin Zhuang, Qiang Hu, Rui Liu, Chenglong Shen, and Yutian Chi, On the twists of interplanetary magnetic flux ropes observed at 1 AU, J. Geophys. Res. - Space Phys., 121, 9316-9339, doi:10.1002/2016JA023075, 2016-10. [(542.8KB), (263.4KB), (3.3MB)] | Abstract. Magnetic flux ropes (MFRs) are one kind of fundamental structures in the solar/space physics and involved in various eruption phenomena. Twist, characterizing how the magnetic field lines wind around a main axis, is an intrinsic property of MFRs, closely related to the magnetic free energy and stableness. Although the effect of the twist on the behavior of MFRs had been widely studied in observations, theory, modeling, and numerical simulations, it is still unclear how much amount of twist is carried by MFRs in the solar atmosphere and in heliosphere and what role the twist played in the eruptions of MFRs. Contrasting to the solar MFRs, there are lots of in situ measurements of magnetic clouds (MCs), the large-scale MFRs in interplanetary space, providing some important information of the twist of MFRs. Thus, starting from MCs, we investigate the twist of interplanetary MFRs with the aid of a velocity-modified uniform-twist force-free flux rope model. It is found that most of MCs can be roughly fitted by the model and nearly half of them can be fitted fairly well though the derived twist is probably overestimated by a factor of 2.5. By applying the model to 115 MCs observed at 1 AU, we find that (1) the twist angles of interplanetary MFRs generally follow a trend of about 0.6 l/R radians, where l/R is the aspect ratio of a MFR, with a cutoff at about 12𝜋 radians AU−1, (2) most of them are significantly larger than 2.5𝜋 radians but well bounded by 2 l/R radians, (3) strongly twisted magnetic field lines probably limit the expansion and size of MFRs, and (4) the magnetic field lines in the legs wind more tightly than those in the leading part of MFRs. These results not only advance our understanding of the properties and behavior of interplanetary MFRs but also shed light on the formation and eruption of MFRs in the solar atmosphere. A discussion about the twist and stableness of solar MFRs are therefore given.
We acknowledge the use of the data from Wind spacecraft. We thank Stephen Kahler from AFRL, USA, for providing the data about the magnetic field line lengths inferred from energetic electron events. We also thank the anonymous referees for their useful comments. The model developed in this work can be run and tested online at http://space.ustc.edu.cn/dreams/ mc_fitting/. This work is supported by the grants from NSFC (41131065, 41574165, 41421063, 41274173, and 41474151), CAS (Key Research ProgramKZZD-EW-01-4), MOEC (20113402110001), and the fundamental research funds for the central universities. |
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| 115. | Wang, Yuming, Quanhao Zhang, Jiajia Liu, Chenglong Shen, Fang Shen, Zicai Yang, T. Zic, B. Vrsnak, D. F. Webb, Rui Liu, S. Wang, Jie Zhang, Q. Hu, and B. Zhuang, On the Propagation of a Geoeffective Coronal Mass Ejection during March 15 - 17, 2015, J. Geophys. Res. - Space Phys., 121, 7423-7434, 2016-09. [(1.68MB)] | Abstract. The largest geomagnetic storm so far, called 2015 St. Patrick’s Day event, in the solar cycle 24 was produced by a fast coronal mass ejection (CME) originating on 15 March 2015. It was an initially west-oriented CME and expected to only cause a weak geomagnetic disturbance. Why did this CME finally cause such a large geomagnetic storm? We try to find some clues by investigating its propagation from the Sun to 1 AU. First, we reconstruct the CME’s kinematic properties in the corona from the SOHO and Solar Dynamics Observatory imaging data with the aid of the graduated cylindrical shell model. It is suggested that the CME propagated to the west ∼33∘±10∘ away from the Sun-Earth line with a speed of about 817 km s−1 before leaving the field of view of the SOHO/Large Angle and Spectrometric Coronagraph (LASCO) C3 camera. A magnetic cloud (MC) corresponding to this CME was measured in situ by the Wind spacecraft 2 days after the CME left LASCO’s field of view. By applying two MC reconstruction methods, we infer the configuration of the MC as well as some kinematic information, which implies that the CME possibly experienced an eastward deflection on its way to 1 AU. However, due to the lack of observations from the STEREO spacecraft, the CME’s kinematic evolution in interplanetary space is not clear. In order to fill this gap, we utilize numerical MHD simulation, drag-based CME propagation model (DBM) and the model for CME deflection in interplanetary space (DIPS) to recover the propagation process, especially the trajectory, of the CME from 30RS to 1 AU under the constraints of the derived CME’s kinematics near the Sun and at 1 AU. It is suggested that the trajectory of the CME was deflected toward the Earth by about 12∘, consistent with the implication from the MC reconstruction at 1 AU. This eastward deflection probably contributed to the CME’s unexpected geoeffectiveness by pushing the center of the initially west-oriented CME closer to the Earth.
We acknowledge the use of the data from SOHO, SDO, and Wind spacecraft and the H𝛼 images from Kanzelhoehe Observatory. SOHO is a mission of international cooperation between ESA and NASA, and SDO is a mission of NASA’s Living With a Star Program. We also acknowledge the discussion of the event with T. Berger, N. Gopalswamy, P. Hess, Y. Liu, K. Marubashi, C. Moestl, T. Rollett, M. Temmer, C.-C. Wu, and S. Yashiro under the ISEST program. We thank the anonymous referees for their constructive comments. This work is supported by grants from NSFC (41131065 and 41421063), CAS (Key Research Program KZZD-EW-01 and 100-Talent Program), and the fundamental research funds for the central universities. Y.W. is also supported by NSFC41574165, C.S. by NSFC41274173, F.S. and Z.Y. by NSFC41474152 and MOST 973 key project 2012CB825601, and R.L. by NSFC 41222031. B.V. and T.Z. acknowledge the financial support by the Croatian Science Foundation under the project 6212 “Solar and Stellar Variability.” |
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| 114. | Liu, Rui, Jun Chen, Yuming Wang, and Kai Liu, Investigating Energetic X-Shaped Flares on the Outskirts of A Solar Active Region, Sci. Rep., 6, 34021, 2016-09. [(3.08MB)] | Abstract. Typical solar flares display two quasi-parallel, bright ribbons on the chromosphere. In between is the polarity inversion line (PIL) separating concentrated magnetic fluxes of opposite polarity in active regions (ARs). Intriguingly a series of flares exhibiting X-shaped ribbons occurred at the similar location on the outskirts of NOAA AR 11967, where magnetic fluxes were scattered, yet three of them were alarmingly energetic. The X shape, whose center coincided with hard X-ray emission, was similar in UV/EUV, which cannot be accommodated in the standard flare model. Mapping out magnetic connectivities in potential fields, we found that the X morphology was dictated by the intersection of two quasi-separatrix layers, i.e., a hyperbolic flux tube (HFT), within which a separator connecting a double null was embedded. This topology was not purely local but regulated by fluxes and flows over the whole AR. The nonlinear force-free field model suggested the formation of a current layer at the HFT, where the current dissipation can be mapped to the X-shaped ribbons via field-aligned heat conduction. These results highlight the critical role of HFTs in 3D magnetic reconnection and have important implications for astrophysical and laboratory plasmas.
We thank the SDO team for the vector magnetic field and EUV imaging data, P.W. Schuck for the flow tracking code, T. Wiegelmann for the NLFFF code, X. Cheng for helpful comments. R.L. acknowledges the support from the Thousand Young Talents Program of China and NSFC 41474151. Y.W. acknowledges the support from NSFC 41131065 and 41574165. This work was also supported by NSFC 41421063, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. |
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| 113. | Zhenpeng Su, Zhonglei Gao, Hui Zhu, Wen Li, Huinan Zheng, Yuming Wang, Shui Wang, H. E. Spence, G. D. Reeves, D. N. Baker, J. B. Blake, H. O. Funsten, and J. R. Wygant, Nonstorm time dropout of radiation belt electron fluxes on 24 September 2013, J. Geophys. Res. - Space Phys., 121, 6400-6416, 2016-08. | |
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| 112. | Chang Yang, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Yuming Wang, Shui Wang, H. E. Spence, G. D. Reeves, D. N. Baker, J. B. Blake, and H. O. Funsten, Rapid flattening of butterfly pitch-angle distributions of radiation belt electrons by whistler-mode chorus, Geophys. Res. Lett., 43, 8339-8347, 2016-08. [(3.55MB)] | |
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| 111. | Liu, Lijuan*, Yuming Wang*, Jingxiu Wang, Chenglong Shen, Pinzhong Ye, Rui Liu, Jun Chen, Quanhao Zhang, and S. Wang, Why is a flare-rich active region CME-poor?, Astrophys. J., 826, 119(10pp), 2016-07. [(5.23MB)] | Abstract. Solar active regions (ARs) are the major sources of two of the most violent solar eruptions, namely flares and coronal mass ejections (CMEs). The largest AR in the past 24 years, NOAA AR 12192, which crossed the visible disk from 2014 October 17 to 30, unusually produced more than one hundred flares, including 32 M-class and 6 X-class ones, but only one small CME. Flares and CMEs are believed to be two phenomena in the same eruptive process. Why is such a flare-rich AR so CME-poor? We compared this AR with other four ARs; two were productive in both and two were inert. The investigation of the photospheric parameters based on the SDO/HMI vector magnetogram reveals that the flare-rich AR 12192, as with the other two productive ARs, has larger magnetic flux, current, and free magnetic energy than the two inert ARs but, in contrast to the two productive ARs, it has no strong, concentrated current helicity along both sides of the flaring neutral line, indicating the absence of a mature magnetic structure consisting of highly sheared or twisted field lines. Furthermore, the decay index above the AR 12192 is relatively low, showing strong constraint. These results suggest that productive ARs are always large and have enough current and free energy to power flares, but whether or not a flare is accompanied by a CME is seemingly related to (1) the presence of a mature sheared or twisted core field serving as the seed of the CME, or (2) a weak enough constraint of the overlying arcades.
We would like to thank our anonymous referee for the careful review and helpful comments which helped us to revise this paper. We acknowledge the use of the data from the HMI and AIA instruments on board Solar Dynamics Observatory (SDO), the MDI and LASCO instruments on board Solar and Heliospheric Observatory (SOHO), and the Geostationary Operational Environmental Satellite (GOES). This work is supported by grants from NSFC (41131065, 41421063, 41274173, 41574165, 41222031, and 41474151), CAS (Key Research Program KZZD-EW-01-4), MOEC (20113402110001), MOST973 key project (2011CB811403), the fundamental research funds for the central universities, and the funds of the Thousand Young Talents Programme of China (R.L). |
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| 110. | Zhang, Quanhao, Yuming Wang, Youqiu Hu, and Rui Liu, Downward Catastrophe of Solar Magnetic Flux Ropes, Astrophys. J., 825, 109(8pp), 2016-07. [(369.8KB)] | Abstract. 2.5-dimensional time-dependent ideal magnetohydrodynamic (MHD) models in Cartesian coordinates were used in previous studies to seek MHD equilibria involving a magnetic flux rope embedded in a bipolar, partially open background field. As demonstrated by these studies, the equilibrium solutions of the system are separated into two branches: the flux rope sticks to the photosphere for solutions at the lower branch but is suspended in the corona for those at the upper branch. Moreover, a solution originally at the lower branch jumps to the upper, as the related control parameter increases and reaches a critical value, and the associated jump is here referred to as an upward catastrophe. The present paper advances these studies in three aspects. First, the magnetic field is changed to be force-free; the system still experiences an upward catastrophe with an increase in each control parameter. Second, under the force-free approximation, there also exists a downward catastrophe, characterized by the jump of a solution from the upper branch to the lower. Both catastrophes are irreversible processes connecting the two branches of equilibrium solutions so as to form a cycle. Finally, the magnetic energy in the numerical domain is calculated. It is found that there exists a magnetic energy release for both catastrophes. The Ampèreʼs force, which vanishes everywhere for force-free fields, appears only during the catastrophes and does positive work, which serves as a major mechanism for the energy release. The implications of the downward catastrophe and its relevance to solar activities are briefly discussed.
This research is supported by Grants from NSFC 41131065, 41574165, 41421063, 41474151, and 41222031, MOEC 20113402110001, CAS Key Research Program KZZD-EW- 01-4, and the Fundamental Research Funds for the Central Universities WK2080000077. R.L. acknowledges the support from the Thousand Young Talents Program of China. |
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| 109. | Liemohn, Michael W., Michael Balikhin, Larry Kepko, Alan Rodger, and Yuming Wang, Editorial: Reviewer Selection Process and New Areas of Expertise in GEMS, J. Geophys. Res. - Space Phys., 121, 5566-5570, 2016-06. [(374.2KB)] | |
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| 108. | XIONG Ming, LIU Ying, LIU Hao, LI Baoquan, ZHENG Jianhua, ZHANG Cheng, XIA Lidong, ZHANG Hongxin, RAO Wei, CHEN Changya, SUN Weiying, WU Xia, DENG Yuanyong, HE Han, JIANG Bo, WANG Yuming, WANG Chuanbing, SHEN Chenglong, ZHANG Haiying, ZHANG Shenyi, YANG Xuan, SANG Peng, and WU Ji, Overview of the Solar Polar Orbit Telescope Project for Space Weather Mission, Chinese J. Space Sci., 36, 245-266, 2016-06. [(4.07MB)] | |
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| 107. | Gou, Tingyu, Rui Liu, Yuming Wang, Kai Liu, Bin Zhuang, Jun Chen, Quanhao Zhang, and Jiajia Liu, Stereoscopic Observation of Slipping Reconnection in A Double Candle-Flame-Shaped Flare, Astrophys. J. Lett., 821, L28(7pp), doi:10.3847/2041-8205/821/2/L28, 2016-04. [(1.97MB), (2.7MB)] | Abstract. The 2011 January 28 M1.4 flare exhibits two side-by-side candle-flame-shaped flare loop systems underneath a larger cusp-shaped structure during the decay phase, as observed at the northwestern solar limb by the Solar Dynamics Observatory. The northern loop system brightens following the initiation of the flare within the southern loop system, but all three cusp-shaped structures are characterized by ∼10 MK temperatures, hotter than the archshaped loops underneath. The “Ahead” satellite of the Solar Terrestrial Relations Observatory provides a top view, in which the post-flare loops brighten sequentially, with one end fixed while the other apparently slipping eastward. By performing stereoscopic reconstruction of the post-flare loops in EUV and mapping out magnetic connectivities, we found that the footpoints of the post-flare loops are slipping along the footprint of a hyperbolic flux tube (HFT) separating the two loop systems and that the reconstructed loops share similarity with the magnetic field lines that are traced starting from the same HFT footprint, where the field lines are relatively flexible. These results argue strongly in favor of slipping magnetic reconnection at the HFT. The slipping reconnection was likely triggered by the flare and manifested as propagative dimmings before the loop slippage is observed. It may contribute to the late-phase peak in Fe XVI 33.5 nm, which is even higher than its main-phase counterpart, and may also play a role in the density and temperature asymmetry observed in the northern loop system through heat conduction.
R.L. acknowledges the support from the Thousand Young Talents Program of China and NSFC 41474151. Y.W. acknowledges the support from NSFC 41131065 and 41574165. This work was also supported by NSFC 41421063, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. |
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| 106. | Liemohn, Michael W., Michael Balikhin, Larry Kepko, Alan Rodger, and Yuming Wang, Editorial: Appreciation of the 2015 JGR Space Physics peer reviewers, J. Geophys. Res. - Space Phys., 121, 3824-3863, 2016-04. [(172.8KB)] | |
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| 105. | Wang, Yuming, Zhenjun Zhou, Jie Zhang, Kai Liu, Rui Liu, Chenglong Shen, and Phillip C. Chamberlin, Thermodynamic Spectrum of Solar Flares Based on SDO/EVE Observations: Techniques and First Results, Astrophys. J. Supp., 223, 4(22pp), 2016-03. [(13.54MB)] | Abstract. The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.
We acknowledge use of data from the SDO, STEREO, SOHO,and GOES spacecraft. SDO is a mission of NASAʼs Living With a Star Program, STEREO is the third mission in NASAʼs Solar Terrestrial Probes program, and SOHO is a mission of international cooperation between ESA and NASA. The TDS charts for all the events involved in this study could be found at http://space.ustc.edu.cn/dreams/shm/tds (the MEGS-A-only TDS) and http://space.ustc.edu.cn/dreams/shm/tds-c09 (the extended TDS). This work is supported by grants from the NSFC (41131065, 41574165, 41421063, 41274173, 41222031, 41404134, and 41474151), CAS (Key Research Program KZZD-EW-01 and 100-Talent Program), MOST 973 key project (2011CB811403), and the fundamental research funds for the central universities. |
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| 104. | Guo, Jianpeng, Fengsi Wei, Xueshang Feng, Jeffrey M. Forbes, Yuming Wang, Huixin Liu, Weixing Wan, Zhiliang Yang, and Chaoxu Liu, Prolonged multiple excitation of large-scale traveling atmospheric disturbances (TADs) by successive and interacting coronal mass ejections, J. Geophys. Res. - Space Phys., 121, 2662-2668, 2016-03. [(4.12MB)] | Abstract. Successive and interacting coronal mass ejections (CMEs) directed earthward can have significant impacts throughout geospace. While considerable progress has been made in understanding their geomagnetic consequences over the past decade, elucidation of their atmospheric consequences remains a challenge. During 17–19 January 2005, a compound stream formed due to interaction of six successive halo CMEs impacted Earth’s magnetosphere. In this paper, we report one atmospheric consequence of this impact, namely, the prolonged multiple excitation of large-scale (>∼1000 km) traveling atmospheric disturbances (TADs). The TADs were effectively excited in auroral regions by sudden injections of energy due to the intermittent southward magnetic fields within the stream. They propagated toward the equator at speeds near 800 m/s and produced long-duration (∼2.5 days) continuous large-scale density disturbances of order up ± 40% in the global thermosphere.
The work is supported by the Chinese Academy of Sciences (KZZD-EW-01-4), the 973 program (2012CB825601), the National Natural Science Foundation of China (41231068, 41374187, and 41531073), and the Specialized Research Fund for State Key Laboratories. J. Forbes is supported by NASAAward NNX12AD26G to the University of Colorado. Y. Wang is supported by NSFC grants 41131065 and 41574165. H. Liu is supported by JSPS KAKENHI grant 15K05301, 15H02135, and 15H03733. Z. Yang is supported by the National Natural Science Foundation of China (U1231104). We acknowledge the use of the satellite data from SOHO, WIND, ACE, CHAMP, and GRACE. The geomagnetic indices (SYM-H and AE) are available at CDAWeb. |
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| 103. | Liu, Jiajia, Fang Fang, Yuming Wang, Scott W. McIntosh, Yuhong Fan, and Quanhao Zhang, On the Observation and Simulation of Solar Coronal Twin Jets, Astrophys. J., 817, 126(8pp), 2016-02. [(2.51MB)] | Abstract. We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jets form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.
We acknowledge the use of data from the AIA instrument on board the Solar Dynamics Observatory (SDO) and the EUVI instrument on board the Solar TErrestrial RElations Observatory (STEREO). This work is supported by grants from the China Postdoctoral Science Foundation (2015M580540), MOST 873 key project (2011CB811403), CAS (Key Research Program KZZD-EW-01-4), NSFC (41131065 and 41121003), MOEC (20113402110001), and the fundamental research funds for the central universities. J.L. did part of this work when he was a student visitor at HAO and supported by the Chinese Scholarship Council (201306340034). F.F. is supported by NASA Grant NNX13AJ04A and the University of Colorados George Ellery Hale Postdoctoral Fellowship. |
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| 102. | Liu, Rui, Bernhard Kliem, Viacheslav S. Titov, Jun Chen, Yuming Wang, Haimin Wang, Chang Liu, Yan Xu, and Thomas Wiegelmann, Structure, Stability, and Evolution of Magnetic Flux Ropes from the Perspective of Magnetic Twist, Astrophys. J., 818, 148(12pp), doi:10.3847/0004-637X/818/2/148, 2016-02. [(7.42MB), (1.32MB)] | Abstract. We investigate the evolution of NOAA Active Region (AR) 11817 during 2013 August 10–12, when it developed a complex field configuration and produced four confined, followed by two eruptive, flares. These C-and-above flares are all associated with a magnetic flux rope (MFR) located along the major polarity inversion line, where shearing and converging photospheric flows are present. Aided by the nonlinear force-free field modeling, we identify the MFR through mapping magnetic connectivities and computing the twist number w for each individual field line. The MFR is moderately twisted (∣w∣ < 2) and has a well-defined boundary of high squashing factor Q. We found that the field line with the extremum ∣w∣ is a reliable proxy of the rope axis, and that the MFRʼs peak ∣w∣ temporarily increases within half an hour before each flare while it decreases after the flare peak for both confined and eruptive flares. This pre-flare increase in ∣w∣ has little effect on the ARʼs free magnetic energy or any other parameters derived for the whole region, due to its moderate amount and the MFRʼs relatively small volume, while its decrease after flares is clearly associated with the stepwise decrease in the whole regionʼs free magnetic energy due to the flare. We suggest that w may serve as a useful parameter in forewarning the onset of eruption, and therefore, the consequent space weather effects. The helical kink instability is identified as the prime candidate onset mechanism for the considered flares.
We thank the anonymous referee for constructive suggestions, the SDO team for the vector magnetic field and EUV imaging data, BBSO staff for the NST observations, P.W. Schuck for the flow tracking code, and Y. Guo and T. Török for helpful comments. R.L. acknowledges the support by the Thousand Young Talents Program of China, NSFC 41222031 and 41474151. This work was also supported by NSFC 41131065, CAS Key Research Program KZZD-EW-01-4, and the fundamental research funds for the central universities. B.K. acknowledges support by the CAS under grant no.2012T1J0017 and by the DFG. V.T. was supported by the NSF SHINE program. C.L., H.W., and Y.X. are supported by NSF under grants AGS 1348513 and 1408703, and by NASA under grants NNX13AG13G and NNX13AF76G. |
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| 101. | Gao, Zhonglei, Zhenpeng Su, Hui Zhu, Fuliang Xiao, Huinan Zheng, Yuming Wang, Chao Shen, and Shui Wang, Intense low-frequency chorus waves observed by Van Allen Probes: Fine structures and potential effect on radiation belt electrons, Geophys. Res. Lett., 43, 967-977, 2016-02. | |
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| 100. | Shen, Fang, Yuming Wang*, Chenglong Shen, and Xueshang Feng, Turn on the super-elastic collision nature of coronal mass ejections through low approaching speed, Sci. Rep., 6, 19576, 2016-01. [(1.23MB)] | Abstract. It has been proved from the observations and numerical simulations that the collision between solar coronal mass ejections (CMEs), the largest plasmoids in the heliosphere, could be super-elastic. This finding suggests that the CMEs’ magnetic energy and thermal energy could be converted into kinetic energy through a more efficient way. However CME collisions are not always super-elastic, which means that this distinct property of plasmoids is probably excited conditionally. As the first attempt, we carry out a series of three-dimensional numerical experiments, and establish a diagram showing the dependence of the collision nature on the CME speed and k-number, the ratio of the CME’s kinetic energy to the CME’s total energy. It is found that the super-elastic nature of CMEs appears at the relatively low approaching speed, and most of the previous case studies are in agreement with this diagram. Our study firmly advances the understanding of the super-elastic property of plasmoids, and does give us new clues to deeply understand why and how the magnetic energy and/or thermal energy of the colliding plasmoids can be converted into kinetic energy in such an efficient way.
We acknowledge the use of the data from Wind spacecraft, and thank the anonymous referees for valuable comments. This work is supported by the grants from MOST 973 key project (2012CB825601, 2011CB811403), the CAS knowledge innovation program (KZZD-EW-01-4), the NSFC projects (41231068, 41174150, 41274192, 41474152, 41131065, 41121063, 41574165 and 41274173), the Specialized Research Fund for State Key Laboratories and the fundamental research funds for the central universities. |
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| 2015 Top |
| 99. | Su, Zhenpeng, Hui Zhu, Fuliang Xiao, Qiugang Zong, Xuzhi Zhou, Huinan Zheng, Yuming Wang, S. Wang, Y.-X. Hao, Zhonglei Gao, Zhaoguo He, Daniel Baker, Harlan Spence, Geoffrey Reeves, J Blake, and John Wygant, Ultra low frequency wave-driven diffusion of radiation belt relativistic electrons, Nat. Comm., 6, 10096, 2015-12. [(7.42MB)] | |
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| 98. | Liu, Jiajia, Yuming Wang, Chenglong Shen, Kai Liu, Zonghao Pan, and S. Wang, A Solar Coronal Jet Event Triggers A Coronal Mass Ejection, Astrophys. J., 813, 115(6pp), doi:10.1088/0004-637X/813/2/115, 2015-11. [(1.71MB), (928.3KB)] | Abstract. In this paper, we present multi-point, multi-wavelength observations and analysis of a solar coronal jet and coronal mass ejection (CME) event. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it to propagate at a high speed of over 1000 km s−1. The jet erupted before the CME and shared the same source region. The temporal and spacial relationship between these two events lead us to the possibility that the jet triggered the CME and became its core. This scenario hold the promise of enriching our understanding of the triggering mechanism of CMEs and their relations to coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the Solar Dynamics Observatory (SDO)/HMI instrument along with the off-limb inverse Y-shaped configuration observed by SDO/ AIA in the 171 Å passband provide the first detailed observation of the three-dimensional reconnection process of a large-scale jet as simulated in Pariat et al. The eruption process of the jet highlights the importance of filament-like material during the eruption of not only small-scale X-ray jets, but likely also of large-scale EUV jets. Based on our observations and analysis, we propose the most probable mechanism for the whole event, with a blob structure overlaying the three-dimensional structure of the jet, to describe the interaction between the jet and the CME.
We acknowledge the use of data from the Solar Dynamics Observatory (SDO), the Solar TErrestrial RElations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO). Animation M1 was generated using the “JHelioviewer” tool (http://www.helioviewer.org). This work is supported by grants from NSFC (41131065, 41121003, and 41574165), CAS (Key Research Program KZZD-EW-01-4), MOST 973 key project (2011CB811403), MOEC (20113402110001), and the fundamental research funds for the central universities. The research leading to these results has also received funding from NSFC 41274173, 41404134 and 41304145. |
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| 97. | Feng, L., Yuming Wang*, Fang Shen, Chenglong Shen, Bernd Inhester, Lei Lu, and Weiqun Gan, Why Does the Apparent Mass of a Coronal Mass Ejection Increase?, Astrophys. J., 812, 70(12pp), 2015-10. [(1.15MB)] | Abstract. Mass is one of the most fundamental parameters characterizing the dynamics of a coronal mass ejection (CME). It has been found that CME apparent mass measured from the brightness enhancement in coronagraphs increases during its evolution in the corona. However, the physics behind it is not clear. Does the apparent mass gain come from the outflow from the dimming regions in the low corona, or from the pileup of the solar wind plasma around the CME? Here we analyze the mass evolution of six CME events. Based on the coronagraph observations from the Solar Terrestrial Relations Observatory, we find that their masses increased by a factor of 1.3–1.7 from 7 to 15 RS, where the occulting effect is negligible. We then adopt the “snow-plow” model to calculate the mass contribution of the piled-up solar wind. The result gives evidence that the solar wind pileup probably makes a non-negligible contribution to the mass increase. In the height range from about 7 to 15 RS, the ratio of the modeled to the measured mass increase is roughly larger than 0.55 though the ratios are believed to be overestimated. It is not clear yet whether the solar wind pileup is a major contributor to the final mass derived from coronagraph observations, but it does play an increasingly important role in the mass increase as a CME moves further away from the Sun.
SOHO and STEREO are projects of international cooperation between ESA and NASA. The SECCHI data are produced by an international consortium of NRL, LMSAL, and NASA GSFC (USA), RAL, and U. Birmingham (UK), MPS (Germany), CSL (Belgium), IOTA, and IAS (France). SDO is a mission of NASA’s Living With a Star Program. L.F. and W.Q.G. are supported by the grants from MOSTC (2011CB811402), NSFC (11522328, 11473070, 11427803, 11233008 and 11273065), NSF of Jiangsu Province (BK2012889), CAS(XDA04076101). Y.W. and C.S. are supported by the grants from MOSTC (2011CB811403), CAS (KZZD-EW-01-4) and NSFC 41131065, 41574165, 41121003 and 41274173). F.S. is supported by the grants from MOSTC (2012CB825601) and NSFC (41174150 and 41474152). L.F. also acknowledges the Youth Innovation Promotion Association, CAS, for financial support. The work of B.I. is supported by DLR contract 50 OC 1301. |
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| 96. | 张卫, 史钰峰, 单旭, 李毅人, 郝新军, 缪彬, 徐春凯, 陈向军, 陆全明, 汪毓明, and 张铁龙, 空间低能离子探测器的紫外响应测试 (in Chinese), 原子核物理评论, 32, 358-362, 2015-09. [(336.5KB)] | |
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| 95. | Gou, Tingyu, Rui, Liu*, and Yuming Wang, Do All Candle-Flame-Shaped Flares Have the Same Temperature Distribution?, Sol. Phys., 290, 2211-2230, 2015-08. [(6.74MB), (6.72MB)] | Abstract. We performed a differential emission measure (DEM) analysis of candle-flameshaped flares observed with the Atmospheric Imaging Assembly onboard the Solar Dynamic Observatory. The DEM profile of flaring plasmas generally exhibits a double peak distribution in temperature, with a cold component around log T ≈ 6.2 and a hot component around log T ≈ 7.0. Attributing the cold component mainly to the coronal background, we propose a mean temperature weighted by the hot DEM component as a better representation of flaring plasma than the conventionally defined mean temperature, which is weighted by the whole DEM profile. Based on this corrected mean temperature, the majority of the flares studied, including a confined flare with a double candle-flame shape sharing the same cusp-shaped structure, resemble the famous Tsuneta flare in temperature distribution, i.e., the cusp-shaped structure has systematically higher temperatures than the rounded flare arcade underneath. However, the M7.7 flare on 19 July 2012 poses very intriguing violation of this paradigm: the temperature decreases with altitude from the tip of the cusp toward the top of the arcade; the hottest region is slightly above the X-ray loop-top source that is co-spatial with the emission-measure-enhanced region at the top of the arcade. This signifies that a different heating mechanism from the slow-mode shocks attached to the reconnection site operates in the cusp region during the flare decay phase.
We are grateful to the SDO team for the free access to the data and the development of the data analysis software. R. Liu acknowledges the Thousand Young Talents Program of China, NSFC 41222031 and 41474151, and NSF AGS-1153226. This work was also supported by NSFC 41131065 and 41121003, 973 key project 2011CB811403, CAS Key Research Program KZZD-EW-01-4, the fundamental research funds for the central universities WK2080000031. |
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| 94. | Song, Hongqiang, Yao Chen, Jie Zhang, Xin Cheng, Bing Wang, Qiang Hu, Gang Li, and Yuming Wang, EVIDENCE OF THE SOLAR EUV HOT CHANNEL AS A MAGNETIC FLUX ROPE FROM REMOTE-SENSING AND IN-SITU OBSERVATIONS, Astrophys. J. Lett., 808, L15(6pp), 2015-07. [(1.37MB)] | |
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| 93. | Liu, Jiajia, Scott W. McIntosh, Ineke De Moortel, and Yuming Wang, On the Parallel and Perpendicular Propagating Motions Visible in Polar Plumes: An Incubator For (Fast) Solar Wind Acceleration?, Astrophys. J., 806, 273(7pp), 2015-06. [(1.5MB)] | |
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| 92. | Su, Zhenpeng, Hui Zhu, Fuliang Xiao, Huinan Zheng, Yuming Wang, Chao Shen, Min Zhang, Shui Wang, C. A. Kletzing, W. S. Kurth, G. B. Hospodarsky, H. E. Spence, G. D. Reeves, H. O. Funsten, J. B. Blake, D. N. Baker, and J. R. Wygant, Disappearance of plasmaspheric hiss following interplanetary shock, Geophys. Res. Lett., 42(9), 3129-3140, 2015-05. | |
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| 91. | Song, H. Q., J. Zhang, Y. Chen, X. Cheng, G. Li, and Y. M. Wang, The first taste of a hot channel in interplanetary space, Astrophys. J., 803, 96(8pp), 2015-04. [(19.52MB)] | |
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| 90. | Liu, Kai, Yuming Wang, Jie Zhang, Xin Cheng, Rui Liu, and Chenglong Shen, Extremely Large EUV Late Phase of Solar Flares, Astrophys. J., 802, 35(9pp), 2015-03. [(3.85MB)] | |
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| 89. | Wang, Yuming, Zhenjun Zhou, Chenglong Shen, Rui Liu, and S. Wang, Investigating plasma motion of magnetic clouds at 1 AU through a velocity-modified cylindrical force-free flux rope model, J. Geophys. Res. - Space Phys., 120, 1543-1565, 2015-03. [(3.76MB)] | |
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| 88. | Zhu, Hui, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Yuming Wang, Chao Shen, Tao Xian, Shui Wang, C. A. Kletzing, W. S. Kurth, G. B. Hospodarsky, H. E. Spence, G. D. Reeves, H. O. Funsten, J. B. Blake, and D. N. Baker, Plasmatrough exohiss waves observed by Van Allen Probes: Evidence for leakage from plasmasphere and resonant scattering of radiation belt electrons, Geophys. Res. Lett., 42(4), 1012-1019, 2015-02. | |
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| 2014 Top |
| 87. | Liu, Rui, Yuming Wang, and Chenglong Shen, Early Evolution of An Energetic Coronal Mass Ejection And Its Relation to EUV Waves, Astrophys. J., 797, 37(15pp), 2014-12. [(8.69MB)] | |
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| 86. | Su, Zhenpeng, Hui Zhu, Fuliang Xiao, Huinan Zheng, Yuming Wang, Q.-G. Zong, Zhaoguo He, Chao Shen, Min Zhang, Shui Wang, C. A. Kletzing, W. S. Kurth, G. B. Hospodarsky, H. E. Spence, G. D. Reeves, H. O. Funsten, J. B. Blake, and D. N. Baker, Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt, J. Geophys. Res. - Space Phys., 119(12), 10023-10040, 2014-12. | |
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| 85. | SHI Liang-Wen, SHEN Cheng-Long*, and WANG Yu-Ming, The interplanetary origins of geomagnetic storm with Dstmin≤-50 nT in 2007—2012, 地球物理学报, 57, 3822-3833, doi:10.6038/cjg20141136, 2014-11. [(4.16MB)] | |
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| 84. | Ding, Liuguan, Gang Li*, Jiang Yong, Guiming Le, Chenglong Shen, Yuming Wang, Yao Chen, Fei Xu, Bin Gu, and Yanan Zhang, Interaction between two coronal mass ejections in the 2013 May 22 large solar energetic particle event, Astrophys. J. Lett., 793, L35(7pp), 2014-09. [(4.06MB)] | |
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| 83. | Shen, Fang, Chenglong Shen, Jie Zhang, Phillip Hess, Yuming Wang, Xueshang Feng, Hongze Cheng, and Yi Yang, Evolution of the 12 July 2012 CME from the Sun to the Earth: Data-constrained three-dimensional MHD simulations, J. Geophys. Res. - Space Phys., 119, 7128-7141, 2014-09. [(3.9MB)] | |
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| 82. | Rui Liu, Viacheslav Titov, Tingyu Gou, Yuming Wang, Kai Liu, and Haimin Wang, An Unorthodox X-Class Long-Duration Confined Flare, Astrophys. J., 790, 8(12pp), 2014-07. [(4.42MB)] | |
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| 81. | Yuming Wang, Boyi Wang, Chenglong Shen, Fang Shen, and Noe Lugaz, Deflected propagation of a coronal mass ejection from the corona to interplanetary space, J. Geophys. Res. - Space Phys., 119, 5117-5132, 2014-07. [(4.99MB)] | |
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| 80. | Zhang, Qanhao, Rui Liu*, Yuming Wang, Chenglong Shen, Kai Liu, Jiajia Liu, and Shui Wang, A prominence eruption driven by flux feeding from chromospheric fibrils, Astrophys. J., 789, 133(9pp), 2014-07. [(4.15MB)] | |
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| 79. | Cheng, X., M. D. Ding, J. Zhang, X. D. Sun, Y. Guo, Y. M. Wang, B. Kliem, and Y. Y. Deng, Formation of a Double-Decker Magnetic Flux Rope in the Sigmoidal Solar Active Region 11520, Astrophys. J., 789, 93(12pp), 2014-07. [(3.68MB)] | |
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| 78. | Shen, Chenglong, Yuming Wang, Zonghao Pan, Bin Miao, Pinzhong Ye, and S. Wang, Full-Halo Coronal Mass Ejections: Arrival at the Earth, J. Geophys. Res. - Space Phys., 119, 5107-5116, 2014-07. [(1.36MB)] | |
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| 77. | Zhenpeng Su, Hui Zhu, Fuliang Xiao, Huinan Zheng, Yuming Wang, Zhaoguo He, Chao Shen, Chenglong Shen, Chuanbing Wang, Rui Liu, Bin Miao, Min Zhang, Shui Wang, Craig Kletzing, William Kurth, George Hospodarsky, Harlan Spence, Geoffrey Reeves, Herbert Funsten, J. Blake, Daniel Baker, and John Wygant, Intense duskside lower-band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons, J. Geophys. Res. - Space Phys., 119, 4266-4273, 2014-06. | |
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| 76. | Zhenpeng Su, Hui Zhu, Fuliang Xiao, Huinan Zheng, Min Zhang, Yong Liu, Chao Shen, Yuming Wang, and Shui Wang, Latitudinal dependence of nonlinear interaction between electromagnetic ion cyclotron wave and terrestrial ring current ions, Phys. Plasmas, 21, doi:10.1063/1.4880036, 2014-05. | |
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| 75. | Wang, Yuming, Multiple magnetic clouds in interplanetary space: A review and perspective (in Chinese), J. Univ. of Sci. & Tech. of China, 44(5), 100-105, 2014-05. [(1.44MB)] | |
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| 74. | H. Q. Song, J. Zhang, X. Cheng, Y. Chen, R. Liu, Y. M. Wang, and B. Li, Temperature evolution of a magnetic flux rope in a failed solar eruption, Astrophys. J., 784, 48(6pp), 2014-03. [(1.4MB)] | |
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| 73. | Jiajia Liu, Yuming Wang*, Rui Liu, Quanhao Zhang, Kai Liu, Chenglong Shen, and S. Wang, When and how does a prominence-like jet gain kinetic energy?, Astrophys. J., 782, 94, 2014-02. [(1.6MB)] | |
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| 72. | Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Zhaoguo He, Hui Zhu, Min Zhang, C Shen, Yuming Wang, S. Wang, Craig Kletzing, William Kurth, George Hospodarsky, Harlan Spence, Geoffrey Reeves, Herbert Funsten, J. Blake, Daniel Baker, and John Wygant, Nonstorm-time dynamics of electron radiation belts observed by the Van Allen Probes, Geophys. Res. Lett., 41, 229-235, 2014-01. | |
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| 2013 Top |
| 71. | Chenglong Shen, Yuming Wang, Zonghao Pan, Min Zhang, Pinzhong Ye, and S. Wang, Full halo coronal mass ejections: Do we need to correct the projection effect in terms of velocity?, J. Geophys. Res. - Space Phys., 118, 6858-6865, doi:10.1002/2013JA018872, 2013-11. [(776.1KB)] | |
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| 70. | Liangwen Shi, Chenglong Shen, Yuming Wang, and Fang Shen, Research Progresses in Modeling the Propagation of Solar Wind Disturbances (in Chinese), Progress in Astron., 3, 267-286, 2013-08. [(13.16MB)] | |
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| 69. | Yuming Wang, Zhenjun Zhou, Jiajia Liu, Chenglong Shen, and Shui Wang, Dynamic process of coronal mass ejections in interplanetary space (in Chinese), 中国科学：地球科学 (SCIENTIA SINICA Terrae), 43(6), 934-950, 2013-06. [(14.89MB)] | |
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| 68. | Su, Z. P., Zhu, H., Xiao, F. L., Zheng, H. N., Shen, C., Wang, Y. M., and Wang, S., Latitudinal dependence of nonlinear interaction between electromagnetic ion cyclotron wave and radiation belt relativistic electrons, J. Geophys. Res. - Space Phys., 118, 3188-3202, doi:10.1002/jgra.50289, 2013-06. | |
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| 67. | Kai Liu, Jie Zhang, Yuming Wang, and Xin Cheng, ON THE ORIGIN OF THE EXTREME-ULTRAVIOLET LATE PHASE OF SOLAR FLARES, Astrophys. J., 768, 150(13pp), 2013-05. [(2.24MB)] | Abstract. Solar flares typically have an impulsive phase that is followed by a gradual phase as best seen in soft X-ray
emissions. A recent discovery based on the EUV Variability Experiment observations on board the Solar Dynamics
Observatory (SDO) reveals that some flares exhibit a second large peak separated from the first main phase peak by
tens of minutes to hours, which is coined as the flare’s EUV late phase. In this paper, we address the origin of the
EUV late phase by analyzing in detail two late phase flares, an M2.9 flare on 2010 October 16 and an M1.4 flare on
2011 February 18, using multi-passband imaging observations from the Atmospheric Imaging Assembly on board
SDO. We find that (1) the late phase emission originates from a different magnetic loop system, which is much
larger and higher than the main phase loop system. (2) The two loop systems have different thermal evolution.
While the late phase loop arcade reaches its peak brightness progressively at a later time spanning for more than
one hour from high to low temperatures, the main phase loop arcade reaches its peak brightness at almost the same
time (within several minutes) in all temperatures. (3) Nevertheless, the two loop systems seem to be connected
magnetically, forming an asymmetric magnetic quadruple configuration. (4) Further, the footpoint brightenings in
UV wavelengths show a systematic delay of about one minute from the main flare region to the remote footpoint
of the late phase arcade system. We argue that the EUV late phase is the result of a long-lasting cooling process in
the larger magnetic arcade system.
SDO is a mission of NASA’s Living With a Star Program.
K.L. and Y.W. are supported by 973 key project 2011CB811403
and NSFC 41131065. K.L. is also supported by the scholarship
granted by the China Scholarship Council (CSC) under file No.
2011634065. J.Z. is supported by NSF grant ATM-0748003,
AGS-1156120, and NASA grant NNG05GG19G. |
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| 66. | Fang Shen, Chenglong Shen, Yuming Wang*, Xueshang Feng, and Changqing Xiang, Could the collision of CMEs in the heliosphere be super-elastic? --- Validation through three-dimensional simulations, Geophys. Res. Lett., 40, 1457-1461, doi:10.1002/grl.50336, 2013-05. [(95.3KB), (310.6KB), (1.32MB)] | Abstract. Though coronal mass ejections (CMEs) are magnetized
fully ionized gases, a recent observational study of a CME
collision event in 2008 November has suggested that their
behavior in the heliosphere is like elastic balls, and their collision
is probably superelastic [C. Shen et al., 2012]. If this is
true, this finding has an obvious impact on the space weather
forecasting because the direction and velocity of CMEs may
change. To verify it, we numerically study the event through
three-dimensional MHD simulations. The nature of CMEs’
collision is examined by comparing two cases. In one case,
the two CMEs collide as observed, but in the other, they
do not. Results show that the collision leads to extra kinetic
energy gain by 3–4% of the initial kinetic energy of the two
CMEs. It firmly proves that the collision of CMEs could be
superelastic.
Acknowledgments. This work is jointly supported by grants
from the 973 key projects (2012CB825601, 2011CB811403), the CAS
Knowledge Innovation Program (KZZD-EW-01-4), the NFSC (41031066,
41074121, 41231068, 41174150, 41274192, 41131065, 41121003 and
41274173), the Specialized Research Fund for State Key Laboratories,
and the Public Science and Technology Research Funds Projects of Ocean
(201005017). |
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| 65. | C. Shen, G. Li, X. Kong, J. Hu, X. D. Sun, L. Ding, Y. Chen, Yuming Wang, and L. Xia, Compound twin coronal mass ejections in the 2012 May 17 GLE event, Astrophys. J., 763, 114, doi:10.1088/0004-637X/763/2/114, 2013-02. [(3.65MB)] | Abstract. We report a multiple spacecraft observation of the 2012 May 17 GLE event. Using the coronagraph observations
by SOHO/LASCO, STEREO-A/COR1, and STEREO-B/COR1, we identify two eruptions resulting in two coronal
mass ejections (CMEs) that occurred in the same active region and close in time (∼2 minutes) in the 2012 May
17 GLE event. Both CMEs were fast. Complicated radio emissions, with multiple type II episodes, were observed
from ground-based stations: Learmonth and BIRS, as well as theWAVES instrument on board the Wind spacecraft.
High time-resolution SDO/AIA imaging data and SDO/HMI vector magnetic field data were also examined.
Acomplicated pre-eruption magnetic field configuration, consisting of twisted flux-tube structure, is reconstructed.
Solar energetic particles (SEPs) up to several hundred MeV nucleon−1 were detected in this event. Although the
eruption source region was near the west limb, the event led to ground-level enhancement. The existence of two
fast CMEs and the observation of high-energy particles with ground-level enhancement agrees well with a recently
proposed “twin CME” scenario.
We are grateful to the STEREO/SECCHI, SOHO/LASCO,
and Learmonth teams for making their data available online. The
SDO data are courtesy of NASA and the HMI and AIA science
teams, and the magnetic field extrapolation code is provided
by Dr. Wiegelmann. We thank Dr. Stephen White and Dr. Bill
Erickson for providing the BIRS data. This work is supported at
UAH by NSF grants ATM-0847719, AGS-0962658 and AGS-
1135432; NASA grants NNX11AO64G and NNX09AP74A; at
SDWHby NNSFC grants 41028004, 40825014, and 40890162;
at USTC by 973 key project 2011CB811403, NSFC 41131065,
40904046, 40874075, and 41121003 and the CASKey Research
Program KZZD-EW-01-4. X.D.S. is supported by NASA contract
NAS5-02139 (HMI) to Stanford University. |
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| 64. | Z. J. Rong, W. X. Wan, C. Shen, T. L. Zhang, A. T. Y. Lui, Yuming Wang, M. W. Dunlop, Y. C. Zhang, and Q.-G. Zong, Method for inferring the axis orientation of cylindrical magnetic flux rope based on single-point measurement, J. Geophys. Res. - Space Phys., 118, 1-13, doi:10.1029/2012JA018079, 2013-01. [(709.3KB)] | |
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| 63. | Chenglong Shen, Chijian Liao, Yuming Wang, Pinzhong Ye, and Shui Wang, Source region of the decameter-Hectometric type II radio burst: Shock-streamer interaction region, Sol. Phys., 282, 543-552, doi:10.1007/s11207-012-0161-z, 2013-01. [(2.93MB)] | Abstract. D–H type II radio bursts are widely thought to be caused by coronal mass ejections
(CMEs). However, it is still unclear where the exact source of the type IIs on the
shock surface is. We identify the source regions of the decameter–hectometric (D–H) type
IIs based on imaging observations from SOHO/LASCO and the radio dynamic spectrum
from Wind/Waves. The analysis of two well-observed events suggests that the sources of
these two events are located in the interaction regions between shocks and streamers, and
that the shocks are enhanced significantly in these regions.
We acknowledge the use the SOHO/LASCO and Wind/Waves observations. The
SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA),
Max-Planck-Institut für Aeronomie (Germany), Laboratoire d’Astrophysique de Marseille (France), and the
University of Birmingham (UK). SOHO is a mission of international cooperation between ESA and NASA.
This work is supported by the CAS Key Research Program (KZZD-EW-01), grants from the 973 key project
2011CB811403, NSFC 41131065, 40904046, 41274173, 40874075, and 41121003, CAS the 100-talent program,
KZCX2-YW-QN511 and startup fund, and MOEC 20113402110001 and the fundamental research
funds for the central universities (WK2080000031 and WK2080000007). |
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| 62. | Yuming Wang, Lijuan Liu, Chenglong Shen, Rui Liu, Pinzhong Ye, and S. Wang, Waiting Times of Quasi-homologous Coronal Mass Ejections from Super Active Regions, Astrophys. J. Lett., 763, L43, doi:10.1088/2041-8205/763/2/L43, 2013-01. [(272.3KB)] | Abstract. Why and how do some active regions (ARs) frequently produce coronal mass ejections (CMEs)? These are key
questions for deepening our understanding of the mechanisms and processes of energy accumulation and sudden
release in ARs and for improving our space weather prediction capability. Although some case studies have been
performed, these questions are still far from fully answered. These issues are now being addressed statistically
through an investigation of the waiting times of quasi-homologous CMEs from super ARs in solar cycle 23. It
is found that the waiting times of quasi-homologous CMEs have a two-component distribution with a separation
at about 18 hr. The first component is a Gaussian-like distribution with a peak at about 7 hr, which indicates a
tight physical connection between these quasi-homologous CMEs. The likelihood of two or more occurrences of
CMEs faster than 1200 km s−1 from the same AR within 18 hr is about 20%. Furthermore, the correlation analysis
among CME waiting times, CME speeds, and CME occurrence rates reveals that these quantities are independent
of each other, suggesting that the perturbation by preceding CMEs rather than free energy input is the direct cause
of quasi-homologous CMEs. The peak waiting time of 7 hr probably characterizes the timescale of the growth of
the instabilities triggered by preceding CMEs. This study uncovers some clues from a statistical perspective for us
to understand quasi-homologous CMEs as well as CME-rich ARs.
We acknowledge the use of data from SOHO/LASCO,
EIT, and MDI and the CDAW CME catalog. SOHO is a
project of international cooperation between ESA and NASA.
This work is supported by grants from the CAS (Key Research
Program KZZD-EW-01 and 100-Talent Program), NSFC
(41131065, 40904046, 40874075, and 41121003), 973 key
project (2011CB811403), MOEC (20113402110001), and the
fundamental research funds for the central universities. R.L. is
also supported by NSF (AGS-1153226). |
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| 2012 Top |
| 61. | Hui Zhu, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Chao Shen, Yuming Wang, and Shui Wang, Nonlinear interaction between ring current protons and electromagnetic ion cyclotron waves, J. Geophys. Res. - Space Phys., 117, A12217, 2012-12. | |
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| 60. | Chenglong Shen, Yuming Wang*, Shui Wang, Ying Liu, Rui Liu, Angelos Vourlidas, Bin Miao, Pinzhong Ye, Jiajia Liu, and Zhenjun Zhou, Super-elastic Collision of Large-scale Magnetized Plasmoids in the Heliosphere, Nat. Phys., 8, 923-928, doi:10.1038/NPHYS2440, 2012-12. [(853KB),  (221.8KB), (19.04MB)] | | Abstract. A super-elastic collision is an unusual process in which some mechanism causes the kinetic energy of the system to increase. Most studies have focused on solid-like objects, and have rarely considered gases or liquids, as the collision of these is primarily a mixing process. However, magnetized plasmoids are different from ordinary gases—as cross-field diffusion is effectively prohibited—but it remains unclear how they behave during a collision. Here we present a comprehensive picture of a unique collision between two coronal mass ejections in the heliosphere, which are the largest magnetized plasmoids erupting from the Sun. Our analysis reveals that these two magnetized plasmoids collided as if they were solid-like objects, with a likelihood of 73% that the collision was super-elastic. The total kinetic energy of the plasmoid system increased by about 6.6% through the collision, significantly influencing its dynamics. |
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| 59. | Rui Liu, Chang Liu, Tibor Torok, Yuming Wang, and Haimin Wang, Contracting and Erupting Components of Sigmoidal Active Regions, Astrophys. J., 757, 150, 2012-09. [(8.73MB)] | |
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| 58. | Zhenpeng Su, Hui Zhu, Fuliang Xiao, Huinan Zheng, C Chen, Yuming Wang, and S. Wang, Bounce-averaged advection and diffusion coefficients for monochromatic electromagnetic ion cyclotron wave: Comparison between test-particle and quasi-linear models, J. Geophys. Res. - Space Phys., 117, A09222, 2012-09. | |
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| 57. | Jiajia Liu, Zhenjun Zhou, Yuming Wang*, Rui Liu, Bin Wang, Chijian Liao, Chenglong Shen, Huinan Zheng, Bin Miao, Zhenpeng Su, and S. Wang, Slow Magnetoacoustic Waves Observed above a Quiet-Sun Region in a Dark Cavity, Astrophys. J. Lett., 758, L26(6pp), 2012-09. [(1.54MB)] | |
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| 56. | Kai Liu, Yuming Wang*, Chenglong Shen, and Shui Wang, Critical Height for the Destabilization of Solar Prominences: Statistical Results from STEREO Observations, Astrophys. J., 744, 168(10pp), 2012-01. [(821.4KB), (1.37MB)] | Abstract. At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06­0.14 R from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R and the second one is 0.19 R . (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R . (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.
We acknowledge the use of data from STEREO/SECCHI, and we are also grateful to the developers of SLIPCAT. We thank Dr. B. C. Low for his reading and valuable comments, and the anonymous referee for his/her constructive comments. This research is supported by grants from the 973 key project 2011CB811403, NSFC 41131065, 40904046, 40874075, and 41121003, the CAS 100-talent program, KZCX2-YW-QN511 and startup fund, FANEDD 200530, and the fundamental research funds for the central universities. |
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| 2011 Top |
| 55. | Caixia Chen, Yuming Wang*, Chenglong Shen, Pinzhong Ye, Jie Zhang, and S. Wang, Statistical study of coronal mass ejection source locations: 2. Role of active regions in CME production, J. Geophys. Res. - Space Phys., 116, A12108, doi:10.1029/2011JA016844, 2011-12. [(658.9KB), (980.9KB)] | Abstract. This is the second paper of the statistical study of coronal mass ejection (CME) source locations, in which the relationship between CMEs and active regions (ARs) is statistically studied on the basis of the information of CME source locations and the ARs automatically extracted from magnetic synoptic charts of Michelson Doppler Imager (MDI) during 1997–1998. Totally, 224 CMEs with a known location and 108 MDI ARs are included in our sample. It is found that about 63% of the CMEs are related with ARs, at least about 53% of the ARs produced one or more CMEs, and particularly about 14% of ARs are CME-rich (3 or more CMEs were generated) during one transit across the visible disk. Several issues are then tried to clarify: whether or not the CMEs originating from ARs are distinct from others, whether or not the CME kinematics depend on AR properties, and whether or not the CME productivity depends on AR properties. The statistical results suggest that (1) there is no evident difference between AR-related and non-AR-related CMEs in terms of CME speed, acceleration and width, (2) the size, strength and complexity of ARs do little with the kinematic properties of CMEs, but have significant effects on the CME productivity, and (3) the sunspots in all the most productive ARs at least belong to bg type, whereas 90% of those in CME-less ARs are a or b type only. A detailed analysis on CME-rich ARs further reveals that (1) the distribution of the waiting time of same-AR CMEs, consists of two parts with a separation at about 15 hours, which implies that the CMEs with a waiting time shorter than 15 hours are probably truly physical related, and (2) an AR tends to produce such related same-AR CMEs at a pace of 8 hours, but cannot produce two or more fast CMEs (>800 km/s) within a time interval of 15 hours. This interesting phenomenon is particularly discussed.
Acknowledgments. We acknowledge the use of the data from SOHO/MDI and the CDAW CME catalog, which is generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory. SOHO is a project of international cooperation between ESA and NASA. We thank the anonymous reviewers for their kindly comments and corrections. This
research is supported by grants from 973 key project 2011CB811403, NSFC 41131065, 40904046, 40874075, 41121003, CAS 100-Talent Program, KZCX2-YW-QN511 and startup fund, FANEDD 200530, and the fundamental research funds for the central universities. J.Z. was supported by NSD grant ATM-0748003 and NASA grant NNG05GG19G. |
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| 54. | F. Shen, X. S. Feng, Yuming Wang, S. T. Wu, W. B. Song, J. P. Guo, and Y. F. Zhou, Three-dimensional MHD simulations of two coronal mass ejections' propagation and Interaction Using a successive magnetized plasma blobs model, J. Geophys. Res. - Space Phys., 116, A09103, doi:10.1029/2011JA016584, 2011-09. [(1.73MB)] | Abstract. A threedimensional (3D), timedependent, numerical magnetohydrodynamic (MHD) model is used to investigate the evolution and interaction of two coronal mass ejections (CMEs) in the nonhomogeneous ambient solar wind. The background solar wind is constructed on the basis of the selfconsistent source surface with observed line of sight of magnetic field and density from the source surface of 2.5 Rs to Earth's orbit (215 Rs) and beyond. The two successive CMEs occurring on 28 March 2001 and forming a multiple magnetic cloud in interplanetary space are chosen as a test case, in which they are simulated by means of a two highdensity, highvelocity, and high temperature magnetized plasma blobs model, and are successively ejected into the nonhomogeneous background solar wind medium along different initial launch directions. The dynamical propagation and interaction of the two CMEs between 2.5 and 220 Rs are investigated. Our simulation results show that, although the two CMEs are separated by 10 h, the second CME is able to overtake the first one and cause compound interactions and an obvious acceleration of the shock. At the L1 point near Earth the two resultant magnetic clouds in our simulation are consistent with the observations by ACE. In this validation study we find that this 3D MHD model, with the selfconsistent source surface as the initial boundary condition and the magnetized plasma blob as the CME model, is able to reproduce and explain some of the general characters of the multiple magnetic clouds observed by satellite.
Acknowledgment. This work is jointly supported by NationalNatural Science Foundation of China (41174150, 41031066, 41074121, 40921063, 40874077, 40890162 and 40874091), the Specialized Research Fund for State Key Laboratories and the Public science and technology research funds projects of ocean (201005017). Y. Wang is supported by 973 Key Project 2011CB811403. S. T. Wu is supported by AFOSR grant FA95500710468, NSF grant ATM0754378, and NSO/AURA grant C10569A, which is a subaward of NSF Award 0132798. We thank the SOHO/LASCO team for letting us use their data. SOHO is a mission of international collaboration between ESA and NASA. The Wilcox Solar Observatory (WSO) data used in this study were obtained via the Web site http://wso.stanford.edu/synopticl.html for CR 1974. The WSO is currently supported by NASA. We also thank ACE Science Center (ASC; http://www.srl.caltech.edu/ACE/ASC/), from which we downloaded the hourly average solar wind data by ACE. The numerical calculation was completed on our SIGMA Cluster computing system. We are very grateful to our anonymous reviewers for the constructive and helpful comments. |
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| 53. | Wang, Yuming, Understanding CMEs from Statistical Results of Their Source Locations, 2011 ILWS Science Workshop "Towards the Next Solar Maximum", , Beijing, China, August 28 - September 1, 2011-09. | |
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| 52. | Bin Gui, Chenglong Shen, Yuming Wang*, Pinzhong Ye, Jiajia Liu, Shui Wang, and Xuepu Zhao, Quantitative Analysis of CME Deflections in the Corona, Sol. Phys., 271, 111-139, doi:10.1007/s11207-011-9791-9, 2011-06. [(5.22MB), (4.32MB)] | Abstract. In this paper, ten CME events viewed by the STEREO twin spacecraft are analyzed
to study the deflections of CMEs during their propagation in the corona. Based on the three-dimensional information of the CMEs derived by the graduated cylindrical shell (GCS) model (Thernisien, Howard, and Vourlidas in Astrophys. J. 652, 1305, 2006), it is found that the propagation directions of eight CMEs had changed. By applying the theoretical method proposed by Shen et al. (Solar Phys. 269, 389, 2011) to all the CMEs, we found that the deflections are consistent, in strength and direction, with the gradient of the magnetic energy density. There is a positive correlation between the deflection rate and the strength of the magnetic energy density gradient and a weak anti-correlation between the deflection rate and the CME speed. Our results suggest that the deflections of CMEs are mainly controlled by the background magnetic field and can be quantitatively described by the magnetic energy density gradient (MEDG) model.
Acknowledgements We acknowledge the use of the data from STEREO/SECCHI and SOHO/MDI. We also acknowledge the use of the GCS model that was developed by A. Thernisien. We are grateful to the anonymous referee for his/her kind and constructive comments. This work is supported by grants from 973 key projects 2011CB811403, NSFC 40874075, 40904046, FANEDD 200530, CAS KZCX2-YW-QN511, 100-Talent program of CAS, and the fundamental research funds for the central universities. |
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| 51. | Z. H. Pan, C. B. Wang, Yuming Wang, and X. H. Xue, Correlation analyses between the characteristic time of gradual solar energetic particle events and the properties of associated coronal mass ejections, Sol. Phys., 270, 593-607, doi:10.1007/s11207-011-9763-0, 2011-05. [(579.7KB)] | Abstract. It is generally believed that gradual solar energetic particles (SEPs) are accelerated by shocks associated with coronal mass ejections (CMEs). Using an ice-cream cone model, the radial speed and angular width of 95 CMEs associated with SEP events during 1998 – 2002 are calculated from SOHO/LASCO observations. Then, we investigate the relationships between the kinematic properties of these CMEs and the characteristic times of the intensity-time profile of their accompanied SEP events observed at 1 AU. These characteristic times of SEP are i) the onset time from the accompanying CME eruption at the Sun to the SEP arrival at 1 AU, ii) the rise time from the SEP onset to the time when the SEP intensity is one-half of peak intensity, and iii) the duration over which the SEP intensity is within a factor of two of the peak intensity. It is found that the onset time has neither significant correlation with the radial speed nor with the angular width of the accompanying CME. For events that are poorly connected to the Earth, the SEP rise time and duration have no significant correlation with the radial speed and angular width of the associated CMEs. However, for events that are magnetically well connected to the Earth, the SEP rise time and duration have significantly positive correlations with the radial speed and angular width of the associated CMEs. This indicates that a CME event with wider angular width and higher speed may more easily drive a strong and wide shock near to the Earth-connected interplanetary magnetic field lines, may trap and accelerate particles for a longer time, and may lead to longer rise time and duration of the ensuing SEP event.
Acknowledgements. ZHP and CBWwere supported by the National Nature Science Foundation (40774076, 40931053, 40874075) and the Chinese Academy of Sciences (KZCX2-YW-QN512). YW was supported by the National 973 key project (2011CB811403). XHX was supported by the Specialized Research Fund for
the Doctoral Program of Higher Education (200803581019). We are grateful for the use of observational data from the SOHO and Yohkoh spacecraft in this paper. The reference of the LASCO CME catalog is also acknowledged. This CME catalog is generated and maintained by the Center for Solar Physics and Space Weather, the Catholic University of America, in cooperation with the Naval Research Laboratory and NASA. |
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| 50. | Yuming Wang, Chenglong Shen, Pinzhong Ye, and Shui Wang, Multiple Magnetic Clouds: A Review and Perspective, International Symposium: From Solar Storm to Geomagnetic Storm, , Shanghai, China, May 9 - 13, 2011-05. | |
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| 49. | Yuming Wang, Caixia Chen, Bin Gui, Chenglong Shen, Pinzhong Ye, and S. Wang, Statistical Study of Coronal Mass Ejection Source Locations: Understanding CMEs Viewed in Coronagraphs, J. Geophys. Res. - Space Phys., 116, A04104, doi: 10.1029/2010JA016101, 2011-04. [(1.03MB)] | Abstract. How to properly understand coronal mass ejections (CMEs) viewed in white light coronagraphs is crucial to many relative researches in solar and space physics. The issue is now particularly addressed in this paper through studying the source locations of all the 1078 Large Angle and Spectrometric Coronagraph (LASCO) CMEs listed in Coordinated Data Analysis Workshop (CDAW) CME catalog during 1997–1998 and their correlation with CMEs’ apparent parameters. By manually checking LASCO and Extreme Ultraviolet Imaging Telescope (EIT) movies of these CMEs, we find that, except 231 CMEs whose source locations cannot be identified due to poor data, there are 288 CMEs with location identified on the frontside solar disk, 234 CMEs appearing above solar limb, and 325 CMEs without evident eruptive signatures in the field of view of EIT. On the basis of the statistical results of CMEs’ source locations, there are four physical issues: (1) the missing rate of CMEs by SOHO LASCO and EIT, (2) the mass of CMEs, (3) the causes of halo CMEs, and (4) the deflections of CMEs in the corona, are exhaustively analyzed. It is found that (1) about 32% frontside CMEs cannot be recognized by SOHO, (2) the brightness of a CME at any heliocentric distance is roughly positively correlated with its speed, and the CME mass derived from the brightness is probably overestimated, (3) both projection effect and violent eruption are the major causes of halo CMEs, and especially for limb halo CMEs the latter is the primary one, and (4) most CMEs deflected toward equator near the solar minimum; these deflections can be classified into three types: the asymmetrical expansion, the nonradial ejection, and the deflected propagation.
Acknowledgments. We acknowledge the use of the data from the CDAW CME catalog, which is generated and maintained at the CDAW Data Center by NASA and the Catholic University of America in cooperation with the Naval Research Laboratory. SOHO is a project of international cooperation between ESA and NASA. We thank J. Zhang at George Mason University for his advice in identifying CMEs’ source locations. This research is supported by grants from 973 key project 2011CB811403; NSFC 40525014, 40874075, 40904046; FANEDD 200530; CAS KZCX2‐YW‐QN511; 100‐Talent Program of CAS; and the fundamental research funds for the central universities. |
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| 48. | Gui, Bin, Chenglong Shen, Yuming Wang, Pinzhong Ye, and S. Wang, Correction of projection effect of CMEs in velocity: Comparing of Forward modeling method and simple angular correction method (Chinese Version), Chinese J. Space Sci., 31(2), 154-164, 2011-03. | |
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| 47. | Liu, Yong C.-M., M. Opher, Yuming Wang, and T. I. Gombosi, Downstream structure and evolution of a simulated CME-driven sheath in the solar corona, Astron. & Astrophys., 527, A46, doi: 10.1051/0004-6361/201014384, 2011-03. [(6.81MB)] | Abstract. Context. The transition of the magnetic field from the ambient magnetic field to the ejecta in the sheath downstream of a coronal mass ejection (CME)-driven shock is analyzed in detail. The field rotation in the sheath occurs in a two-layer structure. In the first layer, Layer 1, the magnetic field rotates in the coplanarity plane (plane of shock normal and the upstream magnetic field), and in Layer 2 rotates o this plane. We investigate the evolution of the two layers as the sheath evolves away from the Sun.
Aims. In situ observations have shown that the magnetic field in the sheath region in front of an Interplanetary coronal mass ejection (ICME) form a planar magnetic structure, and the magnetic field lines drape around the flux tube. Our object is to investigate the magnetic configuration of the CME near the sun.
Methods. We used a 3D Magnetohydrodynamics (MHD) simulation code, the space weather modeling framework (SWMF) to simulate the propagation of CMEs and the shock driven by it.
Results. Close to the Sun, Layer 2 dominates the width of the sheath, diminishing its importance as the sheath evolves away from the Sun, consistent with observations at 1AU. |
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| 46. | Shen, Chenglong, Yuming Wang, Bin Gui, Pinzhong Ye, and Shui Wang, Kinematic Evolution of A Slow CME in Corona Viewed by STEREO-B on October 8, 2007, Sol. Phys., 269, 389-400, 2011-03. [(872.3KB)] | Abstract. We studied the kinematic evolution of the 8 October 2007 CME in the corona based on observations from Sun ­ Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard satellite B of Solar TErrestrial RElations Observatory (STEREO). The observational results show that this CME obviously deflected to a lower latitude region of about 30° at the beginning. After this, the CME propagated radially. We also analyze the influence of the background magnetic field on the deflection of this CME. We find that the deflection of this CME at an early stage may be caused by a nonuniform distribution of the background magnetic-field energy density and that the CME tended to propagate to the region with lower magnetic-energy density. In addition, we found that the velocity profile of this gradual CME shows multiphased evolution during its propagation in the COR1-B FOV. The CME velocity first remained constant: 23.1 km s-1 . Then it accelerated continuously with a positive acceleration of 7.6 m s-2 .
Acknowledgements. We acknowledge the use of the data from STEREO/SECCHI. We thank Jie Zhang for helpful discussions. This work is supported by grants from the National Natural Science Foundation of China (40904046, 40874075, 40525014), the 973 National Basic Research Program (2011CB811403), Ministry of Education of China (200530), the Program for New Century Excellent Talents in University (NCET-08-0524), the Chinese Academy of Sciences (KZCX2-YW-QN511, KJCX2-YW-N28 and the startup fund) and the Fundamental Research Funds for the Central Universities. |
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| 2010 Top |
| 45. | Jie Zhang, Yuming Wang, and Yang Liu, Statistical Properties of Solar Active Regions Obtained from an Automatic Detection System and the Computational Biases, Astrophys. J., 723, 1006-1018, 2010-10. [(1.04MB)] | Abstract. We have developed a computational software system to automate the process of identifying solar active regions
(ARs) and quantifying their physical properties based on high-resolution synoptic magnetograms constructed from Michelson Doppler Imager (MDI; on board the SOHO spacecraft) images from 1996 to 2008. The system, based
on morphological analysis and intensity thresholding, has four functional modules: (1) intensity segmentation
to obtain kernel pixels, (2) a morphological opening operation to erase small kernels, which effectively remove ephemeral regions and magnetic fragments in decayed ARs, (3) region growing to extend kernels to full AR size, and (4) the morphological closing operation to merge/group regions with a small spatial gap. We calculate the basic physical parameters of the 1730 ARs identified by the auto system. The mean and maximum magnetic flux of individual ARs are 1.67 ×1022 Mx and 1.97 ×1023 Mx, while that per Carrington rotation are 1.83 ×1023 Mx and 6.96 ×1023 Mx, respectively. The frequency distributions of ARs with respect to both area size and magnetic flux follow a log-normal function. However, when we decrease the detection thresholds and thus increase the number of detected ARs, the frequency distribution largely follows a power-law function. We also find that the equatorward drifting motion of the AR bands with solar cycle can be described by a linear function superposed with intermittent reverse driftings. The average drifting speed over one solar cycle is 1. 83 ± 0. 04 yr-1 or 0.708 ± 0.015 m s-1 .
We thank the anonymous referee for valuable comments. We acknowledge the usage of SOHO/MDI data. SOHO
is a project of international cooperation between ESA and NASA. J.Z. is supported by NASA grants NNG07AO72G and NSF ATM-0748003. Y.M.W. is supported by 973-key-project 2006CB806304 and NSFC 40525014 of China. |
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| 44. | Shen, Chenglong, Jia Yao, Yuming Wang, Pinzhong Ye, X. P. Zhao, and S. Wang, Influence of Coronal Holes on CMEs in Causing SEP Events, RAA, 10, 1049-1060, 2010-09. [(751.7KB)] | Abstract. The issue of the influence of coronal holes (CHs) on coronal mass ejections (CMEs) in causing solar energetic particle (SEP) events is revisited. It is a continuation and extension of our previous work (Shen et al., 2006), in which no evident effect of CHs on CMEs in generating SEPs were found by statistically investigating 56 CME events. This result is consistent with the conclusion obtained by Kahler in 2004. In this paper, we extrapolate the coronal magnetic field, define CHs as the regions consisting of only open magnetic field lines and perform a similar analysis on this issue for totally 76 events by extending the study interval to the end of 2008. Three key parameters, CH proximity, CH area and CH relative position, are involved in the analysis. The new result confirms the previous conclusion that CHs did not show any evident effect on CMEs in causing SEP events.
We acknowledge the use of the data from the SOHO, Yohkoh and GOES spacecraft, the CH maps from the Kitt Peak Observatory. SOHO is a project of international cooperation between ESA and NASA. This work is supported by grants from the National Natural Science Foundation of China (40904046,40874075,40525014), the 973 National Basic Research Program (2006CB806304), Ministry of Education of China (200530), the Program for NewCentury Excellent Talents in University (NCET-08-0524) and the Chinese Academy of Sciences (KZCX2-YW-QN511, KJCX2-YW-N28 and the startup fund). |
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| 43. | Wang, Yuming, Hao Cao, Junhong Chen, Tengfei Zhang, Sijie Yu, Huinan Zheng, Chenglong Shen, Jie Zhang, and S. Wang, Solar LImb Prominence CAtcher and Tracker (SLIPCAT): An Automated System and Its Preliminary Statistical Results, Astrophys. J., 717(2), 973-986, 2010-06. [(4.82MB)] | Abstract. In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from EUV 304A passband. The characteristic parameters and their evolution, including height, position angle, area, length and brightness, are obtained without manual interventions. By applying the system to the STEREO-B/SECCHI/EUVI 304A data during 2007 April – 2009 October, we obtain a total of 9477 well-tracked prominences and a catalog of these events available online at http://space.ustc.edu.cn/dreams/slipcat/. A detailed analysis of these prominences suggests that the system has a rather good performance. We have obtained several interesting statistical results based on the catalog. Most prominences appear below the latitude of 60 degrees and at the height of about 26 Mm above the solar surface. Most of them are quite stable during the period they are tracked. Nevertheless, some prominences have an upward speed of more than 100 km/s, and some others show significant downward and/or azimuthal speeds. There are strong correlations among the brightness, area and height. The expansion of a prominence is probably one major cause of its fading during the rising or erupting process.
We acknowledge the use of the data from STEREO/SECCHI. This research is supported by grants from NSFC 40525014, 973 key project 2006CB806304, FANEDD 200530, and the fundamental research funds for the central universities.
Referee's Comments
The manuscript presents a new computer code to automatically detect and track off solar limb prominences from EUV images at 304Å wavelength taken by STEREO/SECCHI/EUVI. Furthermore the code can extract relevant parameters describing the detected prominences such as location, size, brightness and motion.
The article is sufficiently well written and concise. The authors present a very good, clear and thorough description of the algorithm together with an evaluation of its performance and limitations. Additionally, they also present some preliminary results from the statistical analysis of the prominences detected by the code in the period from April 2007 to October 2009. Some of the results confirm earlier findings about prominences. The authors even attempt to provide a rationale for the dimming of prominences as they rise. Finally they present a web-based catalogue that can become very useful in studying the evolution prominences.
In my opinion the article presents a new and effective method of automatically detecting and characterizing prominences that is worth divulging to the scientific community. It also shows sufficiently new and relevant results and is of sufficiently high scientific standard that I recommend it being published by the Astrophysical Journal, MAIN journal. |
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| 2009 Top |
| 42. | Yuming Wang, Jie Zhang, and Chenglong Shen, An analytical model probing the internal state of coronal mass ejections based on observations of their expansions and propagations, J. Geophys. Res. - Space Phys., 114, A10104, doi:10.1029/2009JA014360, 2009-10. [(486.9KB)] | Abstract. In this paper, a generic self-similar flux rope model is proposed to probe the internalstate of CMEs in order to understand the thermodynamic process and expansion of CMEs in interplanetary space. Using this model, three physical parameters and their variations with heliocentric distance can be inferred based on coronagraph observations of CMEs' propagation and expansion. One is the polytropic index G of the CME plasma, and the other two are the average Lorentz force and the thermal pressure force inside CMEs. By applying the model to the 8 October 2007 CME observed by STEREO/SECCHI, we find that (1) the polytropic index of the CME plasma increased from initially 1.24 to more than 1.35 quickly and then slowly decreased to about 1.34; it suggests that there be continuously heat injected/converted into the CME plasma and the value of Gamma tends to be 4/3, a critical value inferred from the model for a force-free flux rope; (2) the Lorentz force directed inward while the thermal pressure force outward, and both of them decreased rapidly as the CME moved out; the direction of the two forces reveals that the thermal pressure force is the internal driver of the CME expansion, whereas the Lorentz force prevented the CME from expanding. Some limitations of the model and approximations are discussed meanwhile.
Acknowledgments. We acknowledge the use of the data from STEREO/SECCHI. We thank James Chen and Yong C.-M. Liu for discussions and the referees for valuable comments. Y. Wang and J. Zhang are supported by grants from NASA NNG05GG19G, NNG07AO72G, and NSF ATM-0748003. Y. Wang and C. Shen also acknowledge the support of China grants from NSF 40525014, 973 key project 2006CB806304, and Ministry of Education 200530. |
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| 41. | Yuming Wang, An analytical model to probe the internal state of coronal mass ejections from observations of coronagraphs, The 2nd International Space Weather Scientific Symposium, , Nanjing, China, 2009-10. | |
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| 2008 Top |
| 40. | Chenglong Shen, Yuming Wang, Pinzhong Ye, and S. Wang, Enhancement of Solar Energetic Particles During A Shock-Magnetic Cloud Interacting Complex Structure, Sol. Phys., 252, 409-418, dio:10.1007/s11207-008-9268-7, 2008-10. [(511.2KB)] | Abstract. Abstract The behavior of solar energetic particles (SEPs) in a shock-magnetic cloud interacting complex structure observed by the ACE spacecraft on 5 November 2001 is analyzed. A strong shock causing magnetic field strength and solar wind speed increases of about 41 nT and 300 km s-1 propagated within a precediing magnetic cloud (MC). It is found that an extraordinary SEP enhancement appeared at the high energy 10 MeV proton intensities, and extended over and only over the entire period of the shock-MC structure passing through the spacecraft. Such SEP behavior is much different from the usual picture that the SEPs are depressed in MCs. A comparison of this event with other top SEP events of solar cycle 23 (2000 Bastille Day and 2003 Halloween events) is made, which shows that such an enhancement resulted from the effects of the shock-MC complex structure leading to the highest 10 MeV proton intensity of solar cycle 23. Our analysis suggests that the relatively isolated magnetic field configuration of MCs combined with an embedded strong shock could significantly enhance the SEP intensity; SEPs are accelerated by the shock and confined into the MC. Further, we find that the SEP enhancement at lower energies not only happened within the shock-MC structure, but also after it probably due to the presence of a following MC-like structure. This is consistent with the picture that SEP fluxes could be enhanced in the magnetic topology between two MCs, which was proposed based on numerical simulations by Kallenrode and Cliver (2001b).
Acknowledgements. We acknowledge the use of the data from the ACE, GOES and Wind spacecraft. We also acknowledge the use of the CME catalog generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory, the list of Type II radio bursts compiled by M. Kaiser at GSFC and the solar event reports from NOAA/SEC. We thank Dr. R. Skoug for providing the best available solar wind plasma data during 5-6 November 2001. We are also grateful to the anonymous referee for many kindly suggestions and corrections. This work is supported by the grants from the National Natural Science Foundation of China (40574063, 40525014), the 973 National Basic Research Program (2006CB806304), the Chinese Academy of Sciences (KZCX3-SW-144 and the startup fund), and the ministry of Education of China (200530, NCET-04-0578). This work is also supported by Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of China. |
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| 39. | Yuming Wang and Jie Zhang, A Statistical Study of Solar Active Regions that Produce Extremely Fast Coronal Mass Ejections, Astrophys. J., 680, 1516-1522, 2008-06. [(330.1KB)] | Abstract. We present a statistical result on the properties of solar source regions that have produced 57 fastest front-side coronal mass ejections (CMEs) (speed 1500 km s-1 ) occurred from 1996 June to 2007 January. The properties of these fast-CME-producing regions, 35 in total, are compared with those of all 1143 active regions (ARs) in the period studied. An automated method, based on SOHO/MDI magnetic synoptic charts, is used to select and characterize the ARs. For each AR, a set of parameters are derived including the areas (positive, negative and total, denoted by A_P , A_N and A_T respectively), the magnetic fluxes (positive, negative and total, F_P , F_N and F_T respectively), the average magnetic field strength (B_avg), quasi-elongation (e) characterizing the overall shape of the AR, the number and length of polarity inversion lines (PILs, or neutral lines, N_PIL and L_PIL respectively), and the average and maximum of magnetic gradient on the PILs (GOP_avg and GOP_max respectively). Our statistical analysis shows a general trend between the scales of an AR and the likelihood of producing a fast CME, i.e., the larger the geometric size (A_T), the larger the magnetic flux (F_T), the stronger the magnetic field (B_avg), and/or the more complex the magnetic configuration (N_PIL and L_PIL), then the higher the possibility of producing a fast CME. When all ARs are sorted into three equally-numbered groups with low, middle and high values of these parameters, we find that, for all these AR parameters, more than 60% of extremely fast CMEs are from the high-value group. The two PIL parameters are the best indicators of producing fast CMEs, with more than 80% from the high value group.
Acknowledgement. We acknowledge the use of the solar data from the MDI, LASCO, and EIT instruments on board SOHO spacecraft. The SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA), Max-Planck-Institut fuer Aeronomie (Germany), Laboratoire d'Astronomie (France), and the University of Birmingham (UK). SOHO is a pro ject of international cooperation between ESA and NASA. We also acknowledge the use of CME catalog generated and maintained at the CDAW Data Center by NASA and The Catholic University of America in cooperation with the Naval Research Laboratory, and the flare list compiled by the Space Environment Center of NOAA. This work is supported by NSF SHINE grant ATM-0454612 and NASA grant NNG05GG19G. Y. Wang is also supported by the grants from NSF of China (40525014) and MSTC (2006CB806304), and J. Zhang is also supported by NASA grants NNG04GN36G. |
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| 38. | Fuliang Xiao, C. L. Shen, Yuming Wang, Huinan Zheng, and S. Wang, Energetic electron distributions fitted with a relativistic kappa-type function at geosynchronous orbit, J. Geophys. Res. - Space Phys., 113, A05203, doi:10.1029/2007JA012903, 2008-05. [(1.33MB)] | Abstract. In this study, we utilize a recently introduced relativistic kappa-type (KT) distribution function to model the omnidirectional differential flux of energetic electrons observed by the SOPA instrument on board the 1989- 046 and LANL-01A satellites at geosynchronous orbit. We derive a useful correlation between the differential flux and the distribution of particles which can directly offer those best fitting parameters (e.g., the number density N, the thermal characteristic speed and the spectral index ) strongly associated with evaluation of the electromagnetic wave instability. We adopt the assumption of a nearly isotropic pitch-angle distribution (PAD) and the typical LMFIT function in the program IDL to perform a non-linear least squared fitting, and find that the new KT distribution fits well with the observed data during different universal times both in the lower and higher energies. We also carry out the direct comparisons with the generalized Lorentzian (kappa) distribution and find that kappa distribution fits well with observational data at the relatively lower energies but display deviations at higher energies, typically above hundreds of keV. Furthermore, the fitting spectral index basically takes 4, 5 or 6 while the fitting parameters N and are quite different due to different differential fluxes of electrons at different universal times. These results, which are applied to the case of a nearly isotropic PAD, demonstrate that the particle flux satisfies the power-law not only at the lower energies but also at the relativistic energies, and the new KT distribution may present valuable insights into the dynamical features in those space plasmas (e.g., the Earth's outer radiation belts and the inner Jovian magnetosphere) where highly energetic particles exist.
Acknowledgments. This work is supported by the National Natural Science Foundation of China grants 40774078, 40774077; the Chinese Academy of Sciences Grant No.KZCX3-SW-144 and the National Key Basic Research Special Foundation of China Grant No. 2006CB806304. |
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| 2007 Top |
| 37. | Chenglong Shen, Yuming Wang*, Pinzhong Ye, X. P. Zhao, Bin Gui, and S. Wang, Strength of Coronal Mass Ejection-Driven Shocks Near the Sun, and Its Importance in Predicting Solar Energetic Particle Events, Astrophys. J., 670, 849-856, doi:10.1086/521716, 2007-11. [(2.45MB)] | Abstract. Coronal shocks are important structures, but there are no direct observations of them in solar and space physics. The strength of shocks plays a key role in shock-related phenomena, such as radio bursts and solar energetic particle (SEP) ´generation. This paper presents an improved method of calculating Alfven speed and shock strength near the Sun. This method is based on using as many observations as possible, rather than one-dimensional global models. Two events, a relatively slow CME on 2001 September 15 and a very fast CME on 2000 June 15, are selected to illustrate the calculation process. The calculation results suggest that the slow CME drove a strong shock, with Mach number of 3.43 4.18, while the fast CME drove a relatively weak shock, with Mach number of 1.90 ­3.21. This is consistent with the radio observations, which find a stronger and longer decameter-hectometric ( DH ) type II radio burst during the first event, and a short DH type II radio burst during the second event. In particular, the alculation results explain the observational fact that the slow CME produced a major solar energetic particle (SEP) event, while the fast CME did not. Through a comparison of the two events, the importance of shock strength in predicting SEP events is addressed.
We acknowledge the use of the data from the LASCO and EIT instruments on board SOHO, the Wind/Waves instrument, the GOES satellites, the ACE/EPAM instrument, and WSO. SOHO is a project of international cooperation between ESA and NASA. We thank Yihua Yan and Shujuan Wang for help in analyzing radio bursts. We are grateful to the referee's comments and suggestions. This work is supported by grants from the NSF of China (40574063, 40525014, 40336052, 40404014), the 973 project (2006CB806304), the Chinese Academy of Sciences (KZCX3-SW-144 and the startup fund), the Program for New Century Excellent Talents in University (NCET-04-0578), and the Ministry of Education (200530). |
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| 36. | Ming Xiong, Huinan Zheng, S. T. Wu, Yuming Wang, and Shui Wang, Magnetohydrodynamic Simulation of the Interaction between Two Interplanetary Magnetic Clouds and its Consequent Geoeffectiveness, J. Geophys. Res. - Space Phys., 112, A11103, doi:10.1029/2007JA012320, 2007-11. [(12.95MB)] | Abstract. Numerical studies of the interplanetary ``multiple magnetic clouds (Multi-MC)'' are performed by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. Both slow MC1 and fast MC2 are initially emerged along the heliospheric equator, one after another with different time intervals. The coupling of two MCs could be considered as the comprehensive interaction between two systems, each comprising of an MC body and its driven shock. The MC2-driven shock and MC2 body are successively involved into interaction with MC1 body. The momentum is transferred from MC2 to MC1. After the passage of MC2-driven shock front, magnetic field lines in MC1 medium previously compressed by MC2-driven shock are prevented from being restored by the MC2 body pushing. MC1 body undergoes the most violent compression from the ambient solar wind ahead, continuous penetration of MC2-driven shock through MC1 body, and persistent pushing of MC2 body at MC1 tail boundary. As the evolution proceeds, the MC1 body suffers from larger and larger compression, and its original vulnerable magnetic elasticity becomes stiffer and stiffer. So there exists a maximum compressibility of Multi-MC when the accumulated elasticity can balance the external compression. This cutoff limit of compressibility mainly decides the maximally available geoeffectiveness of Multi-MC because the geoeffectiveness enhancement of MCs interacting is ascribed to the compression. Particularly, the greatest geoeffectiveness is excited among all combinations of each MC helicity, if magnetic field lines in the interacting region of Multi-MC are all southward. Multi-MC completes its final evolutionary stage when the MC2-driven shock is merged with MC1-driven shock into a stronger compound shock. With respect to Multi-MC geoeffectiveness, the evolution stage is a dominant factor, whereas the collision intensity is a subordinate one. The magnetic elasticity, magnetic helicity of each MC, and compression between each other are the key physical factors for the formation, propagation, evolution, and resulting geoeffectiveness of interplanetary Multi-MC.
Acknowledgments. This work was supported by the National Key Basic Research Special Foundation of China (2006CB806304), the Chinese Academy of Sciences grant KZCX3-SW-144, the National Natural Science Foundation of China (40336052, 40404014, 40525014, 40574063, and 40774077), and the Chinese Academy of Sciences (startup fund). S. T. Wu was supported by an NSF grant (ATM03-16115). |
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| 35. | Guiping Zhou, Jingxiu Wang, Yuming Wang, and Yuzong Zhang, Quasi-simultaneous Flux Emergence in the Events of October/November 2003, Sol. Phys., 244, 13-24, 2007-08. [(698.3KB)] | | Abstract. From late October to the beginning of November 2003, a series of intense solar eruptive events took place on the Sun. More than six active regions (ARs), including three large ARs (NOAA numbers AR 10484, AR 10486, and AR 10488), were involved in the activity. Among the six ARs, four of them bear obviously quasi-simultaneous emergence of magnetic flux. Based on the global Hα and SOHO/EIT EUV observations, we found that a very long filament channel went through the six ARs. This implies that there is a magnetic connection among these ARs. The idea of large-scale magnetic connectivity among the ARs is supported by the consistency of the same chirality in the three major ARs and in their associated magnetic clouds. Although the detailed mechanisms for the quasi-simultaneous flux emergence and the large-scale flux system formation need to be extensively investigated, the observations provide new clues in studying the global solar activity. |
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| 34. | Yuming Wang, Chenglong Shen, Pinzhong Ye, and S. Wang, Comparison of Space Weather Effects of Two Major Coronal Mass Ejections in Late 2003, J. Univ. of Sci. & Tech. of China, 37, 859-867, 2007-08. [(965.3KB)] | Abstract. Two similar major coronal mass ejections (CMEs) occurring on October 28 and November 18, 2003 were reported. Through the comparison of the two CMEs as well as their interplanetary responses, two primary space weather effects of them, i.e., solar energetic particle events and geomagnetic storms, were studied. The associated solar activities of both CMEs involved at least one large flare, a preceding minor fast CME and an eruption of filament. An extremely intense gradual SEP event was produced by the former CME, but no major SEP event appeared after the latter. However, they both caused a great geomagnetic storm and the storm created by the latter CME was slightly larger than the former. By analyzing observations of the two CMEs, their associated activities and the corresponding interplanetary magnetic clouds (MCs), the reason why the two similar major CMEs caused different consequences in the geo-space were discussed. The difference between the two CMEs with respect of SEP events is due to the evident different release rate of energy, and the similarity and difference in geomagnetic storms are related to the MC orientations and the paths along which the Earth intersects the MCs.
We acknowledge the use of the data from the SOHO, ACE, GOES spacecraft, the Halpha images from the YNAO and KSO, and the Dst index from the World Data Center. We thank Drs. Skoug R, Terasawa T, Zurbuchen T, and Raines J for providing the best available solar wind plasma data collected during October 29~30. We also thank Dr. Zhou G P for preparing parts of Fig. 1 and 2. |
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| 33. | Yuming Wang and Jie Zhang, A Comparative Study between Eruptive X-class Flares Associated with Coronal Mass Ejections and Confined X-class Flares, Astrophys. J., 665, 1428-1438, 2007-05. [(1.23MB)] | Abstract. We examine the two kinds of major energetic phenomena that occur in the solar atmosphere: eruptive and confined events. The former describes flares with associated coronal mass ejections (CMEs), while the latter denotes flares without associated CMEs. We find that about 90% of X-class flares are eruptive, but the remaining 10% are confined. To probe why the largest energy releases could be either eruptive or confined, we investigate four X-class events from each of the two types. Both sets of events are selected to have very similar intensities (X1.0 to X3.6) and duration (rise time under 13 minutes and decay time not over 9 minutes) in soft X-ray observations, to reduce any bias due to flare size on CME occurrence. We find that the occurrence of eruption (or confinement) is sensitive to the displacement of the location of the energy release, defined as the distance between the flare site and the flux-weighted magnetic center of the source active region. The displacement is 6 - 17 Mm for confined events but as large as 22 - 37 Mm for eruptive events. This means that confined events occur closer to the magnetic center, while the eruptive events tend to occur close to the edge of active regions. We use the potential field source-surface model to infer the coronal magnetic field above the source active regions and calculate the flux ratio of low (<1.1 Rs) to high (>1.1 Rs) corona. We find that the confined events have a lower ratio (<5.7) than the eruptive events (>7.1). These results imply that a stronger overlying arcade field may prevent energy releases in the low corona from being eruptive, resulting in flares, but without CMEs.
We acknowledge the use of the solar data from the LASCO, EIT, and MDI instruments on board the SOHO spacecraft. The SOHO LASCO data used here are produced by a consortium of the Naval Research Laboratory (US), the Max-Planck-Institut fur Aeronomie (Germany), the Laboratoire d'Astronomie (France), and the University of Birmingham (UK). SOHO is a project of international cooperation between ESA and NASA. We also acknowledge the use of the CME catalog generated and maintained at the CDAW Data Center by NASA and the Catholic University of America in cooperation with the Naval Research Laboratory, and the solar event reports compiled by the Space Environment Center of NOAA. We are grateful for useful discussion with X.-P. Zhao at Stanford University, who provided the procedures for the PFSS model. This work is supported by NSF SHINE grant ATM 04-54612 and NASA grant NNG05GG19G. Y. W. is also supported by grants from the National Natural Science Foundation of China (40525014) and the Ministry of Science and Technology (2006CB806304), and J. Z. is also supported by NASA grant NNG04GN36G. |
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| 32. | XIA Qian (夏倩), SHEN Chenglong (申成龙), WANG Yuming (汪毓明), and YE Pinzhong (叶品中), Role of Expansion Velocity of Magnetic Clouds in Flux Rope Model, Chinese J. Space Sci., 27(4), 271-278, 2007-04. [(1.64MB)] | Abstract. In order to examine the influence of magnetic cloud's expansion on its cylindrical flux rope model, The parameters of MC of 15 typical magnetic clouds with Dst_min < -50 nT during 1998 - 2003 are fitted by applying static and expanding flux rope models, the Multi-MC events and the shock propagation in MC events are not taken into account. It is found that the RMS deviations of the fitting results by the expanding model are all less than or equal to those by the static model, it is better than 30%. That the peak of the magnetic field in MC is at the leading end in the expanding model, it is more consistence with the observations than static model. The inferred expansion speeds of these magnetic clouds are consistent with previous statistical results that the expanding speed of MC is at the order of background Alfven speed. Thus the expanding model matches much more to observed magnetic clouds than the static model. Some differences of the fitted magnetic clouds' parameters between the two models are analyzed.
The work is supported by the grants from the National Natural Science Foundation of China (40404014, 40525014), the Ministry of Sciences and Technology of China (973 project 2006CB806304), the Program for New Century Excellent Talents in University (NCET-04-0578), the Chinese Academy of Sciences (startup fund) and National Key Laboratory of Space Weather. |
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| 31. | Wang, Yuming, Pinzhong Ye, and Shui Wang, The dependence of the geoeffectiveness of interplanetary flux rope on its orientation, with possible application to geomagnetic storm prediction, Sol. Phys., 240, 373-386, 2007-04. [(1.07MB)] | Abstract. Interplanetary magnetic clouds (MCs) are one of the main sources of large non-recurrent geomagnetic storms. With the aid of a force-free flux rope model, the dependence of the intensity of geomagnetic activity (indicated by $Dst$ index) on the axial orientation (denoted by $theta$ and $phi$ in GSE coordinates) of the magnetic cloud is analyzed theoretically. The distribution of the Dst values in the ($theta$, $phi$) plane is calculated by changing the axial orientation for various cases. It is concluded that (i) geomagnetic storms tend to occur in the region of $theta<0^circ$, especially in the region of $thetalsim-45^circ$, where larger geomagnetic activity could be created; (ii) the intensity of geomagnetic activity varies more strongly with $theta$ than with $phi$; (iii) when the parameters $B_0$ (the magnetic field strength at the flux rope axis), $R_0$ (the radius of the flux rope), or $V$ (the bulk speed) increase, or $|D|$ (the shortest distance between the flux rope axis and the $x$-axis in GSE coordinates) decrease, a flux rope not only can increase the intensity of geomagnetic activity, but also is more likely to create a storm, however the variation of $n$ (the density) only has a little effect on the intensity; (iv) the most efficient orientation (MEO) in which a flux rope can cause the largest geomagnetic activity appears at $phisim0^circ$ or $sim180^circ$, and some value of $theta$ which depends mainly on $D$; (v) the minimum $Dst$ value that could be caused by a flux rope is the most sensitive to changes in $B_0$ and $V$ of the flux rope, and for a stronger and/or faster MC, a wider range of the orientation will be geoeffective. Further, through analyzing 20 MC-caused moderate to large geomagnetic storms during 1998 -- 2003, a long-term prediction of MC-caused geomagnetic storms on the basis of the flux rope model is proposed and assessed. The comparison between the theoretical results and the observations shows that there is a close linear correlation between the estimated and observed minimum $Dst$ values. This suggests that using the ideal flux rope to predict practical MC-caused geomagnetic storms is applicable. The possibility of the long-term prediction of MC-caused geomagnetic storms is discussed briefly.
We acknowledge the use of the interplanetary magnetic field and solar wind plasma data from the ACE spacecraft and the Dst index from the World Data Center for Geomagnetism at Kyoto University. We thank C. B. Wang for helpful discussion on the Dst model. We also express our thanks to Judy Karpen for partially improving the language of this paper. We thank the anonymous referee for improving the paper in both the scientific content and the language. This work is supported by the grants from the NSF of China (40525014, 40404014, 40336052), the CAS (KZCX3-SW-144 and startup fund), the MOST of China (2006CB806304), and the Program for New Century Excellent Talents in University (NCET-04-0578). |
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| 2006 Top |
| 30. | Xiong, Ming, Huinan Zheng, Yuming Wang, and Shui Wang, Magnetohydrodynamic Simulation of the Interaction between Interplanetary Strong Shock and Magnetic Cloud and its Consequent Geoeffectiveness 2: Oblique Collision, J. Geophys. Res. - Space Phys., 111, A11102, doi:10.1029/2006JA011901, 2006-11. [(4.51MB)] | Abstract. Numerical studies of the interplanetary "shock overtaking magnetic cloud (MC)" event are continued by a 2.5 dimensional magnetohydrodynamic (MHD) model in heliospheric meridional plane. Interplanetary direct collision (DC)/oblique collision (OC) between an MC and a shock results from their same/different initial propagation orientations. For radially erupted MC and shock in solar corona, the orientations are only determined respectively by their heliographic locations. OC is investigated in contrast with the results in DC [Xiong et al., 2006]. The shock front behaves as a smooth arc. The cannibalized part of MC is highly compressed by the shock front along its normal. As the shock propagates gradually into the preceding MC body, the most violent interaction is transferred sideways with an accompanying significant narrowing of the MC's angular width. The opposite deflections of MC body and shock aphelion in OC occur simultaneously through the process of the shock penetrating the MC. After the shock\'s passage, the MC is restored to its oblate morphology. With the decrease of MC-shock commencement interval, the shock front at 1 AU traverses MC body and is responsible for the same change trend of the latitude of the greatest geoeffectiveness of MC-shock compound. Regardless of shock orientation, shock penetration location regarding the maximum geoeffectiveness is right at MC core on the condition of very strong shock intensity. An appropriate angular difference between the initial eruption of an MC and an overtaking shock leads to the maximum deflection of the MC body. The larger the shock intensity is, the greater is the deflection angle. The interaction of MCs with other disturbances could be a cause of deflected propagation of interplanetary coronal mass ejection (ICME).
This work was supported by the National Natural Science Foundation of China (40336052, 40404014, 40525014, and 40574063), the Chinese Academy of Sciences (startup fund), and the National Key Basic Research Special Foundation of China(2006CB806304). M. Xiong was also supported by Innovative Fund of University of Science and Technology of China for Graduate Students (KD2005030). |
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| 29. | Yuming Wang, Guiping Zhou, Pinzhong Ye, S. Wang, and Jingxiu Wang, A Study on The Orientation of Interplanetary Magnetic Clouds and Solar Filaments, Astrophys. J., 651, 1245-1255, 2006-08. [(1.89MB)] | Abstract. Interplanetary magnetic clouds (MCs), a subset of coronal mass ejections (CMEs), are considered to be one of the main sources of geomagnetic storms. Understanding and predicting the magnetic field configuration of MCs by using solar observations, and therefore providing a longer-term prediction of MC-caused geomagnetic storms is an important topic in solar-terrestrial physics and space weather. As a kind of associated eruptive phenomena of CMEs, solar eruptive filaments provide some information in this aspect. Prior to their eruption, the long axis of filaments is thought to be parallel to the axis of surrounding arcade coronal magnetic fields that erupt and develop into interplanetary magnetic clouds. Through investigating three events during August 2000, October 2000 and November 2003, in which the MC and filament were unambiguously associated with the same eruptive solar event, the axial orientations of the MCs are estimated and compared with the filament orientations quantitatively. By defining `tilt angle' as an angle between a pro jected orientation on the plane of the sky and the ecliptic plane, we find that the tilt angle of these MC axes are about 30 , 60 , and 55 , respectively. However, H images show that the associated filaments were all highly curved. The tilt angles of the long axes of these filaments prior to their eruption vary in a range that corresponds to tangents along the entire curved path of the filaments. These ranges are [0 , 75 ], [-15 , 30 ], and [-25 , 110 ], respectively. The comparison between the MCs and filaments shows that for the first and third events, the estimated MC tilt angles are within the ranges of the tilt angles of the associated filaments, and almost parallel to the central parts of the filaments. But for the second event, the MC tilt angle is out of the range suggested by the tilt angle of the filament. This work suggests that (1) the curvature of filaments should be considered in studying the relation between filament and MC's orientation, (2) inconsistencies between MC orientation and filament orientation do occur, even if the curvature of filaments is taken into account, and (3) the largest deviation between the tilt angle of filaments prior to eruption and the tilt angle of associated MCs occurs for those MCs whose estimated axial orientations are not perpendicular to the Earth-Sun line, indicating that the measured part of the MC is not the leading front of the MC.
We acknowledge the use of solar data from the LASCO, EIT, and MDI instruments on board the SOHO spacecraft, interplanetary data from the ACE spacecraft, and H images from Kanzelho¨he Solar Observatory, BBSO, and YNAO. SOHO is a project of international cooperation between ESA and NASA. We thank the anonymous referee for many constructive suggestions and criticisms. We also thank Jie Zhang, Arthur I. Poland, and Oscar A. Olmedo for comments and proofreading. This work was supported by grants from the National Natural Science Foundation of China (40525014, 40404014, 40336052, 40336053), the 973 Project (2006CB806304), and the Chinese Academy of Sciences (KZCX3-SW-144 and Startup Fund). |
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| 28. | M. Xiong, H. N. Zheng, Yuming Wang, and S. Wang, Magnetohydrodynamic simulation of the interaction between interplanetary strong shock and magnetic cloud and its consequent geoeffectiveness, J. Geophys. Res. - Space Phys., 111, A08105, doi:10.1029/2005JA011593, 2006-08. [(4.88MB)] | Abstract. Numerical studies have been performed to interpret the observed ``shock overtaking magnetic cloud (MC)" event by a 2.5 dimensional magnetohydrodynamic (MHD) model in the heliospheric meridional plane. Results of an individual MC simulation show that the MC travels with a constant bulk flow speed. The MC is injected with a very strong inherent magnetic field over that in the ambient flow and expands rapidly in size initially. Consequently, the diameter of the MC increases in an asymptotic speed while its angular width contracts gradually. Meanwhile, simulations of MC-shock interaction are also presented, in which both a typical MC and a strong fast shock emerge from the inner boundary and propagate along the heliospheric equator, separated by an appropriate interval. The results show that the shock first catches up with the preceding MC, then penetrates through the MC, and finally merges with the MC-driven shock into a stronger compound shock. The morphologies of shock front in interplanetary space and MC body behave as a central concave and a smooth arc, respectively. The compression and rotation of the magnetic field serve as an efficient mechanism to cause a large geomagnetic storm. The MC is highly compressed by the overtaking shock. Contrarily, the transport time of the incidental shock influenced by the MC depends on the interval between their commencements. Maximum geoeffectiveness results from when the shock enters the core of preceding MC, which is also substantiated to some extent by a corresponding simplified analytic model. Quantified by the Dst index, the specific result is that the geoeffectiveness of an individual MC is largely enhanced with 80% increment in maximum by an incidental shock.
This work was supported by the National Natural Science Foundation of China (40274050, 40404014, 40336052 and 40525014), and the Chinese Academy of Sciences (startup fund). M. Xiong was also supported by Innovative Fund of University of Science and Technology of China for Graduate Students (KD2005030). |
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| 27. | Wang, Yuming, Xianghui Xue, Chenglong Shen, Pinzhong Ye, S. Wang, and Jie Zhang, Impact of major coronal mass ejections on geospace during 2005 September 7 - 13, Astrophys. J., 646, 625-633, 2006-07. [(1.06MB)] | Abstract. We have analyzed five ma jor CMEs originating from NOAA active region (AR) 808 during the period of September 7 to 13, 2005, when the AR 808 rotated from the east limb to near solar meridian. Several factors that affect the probability of the CMEs' encounter with the Earth are demonstrated. The solar and interplanetary observations suggest that the 2nd and 3rd CMEs, originating from E 67 and E 47 respectively, encountered the Earth, while the 1st CME originating from E 77 missed the Earth, and the last two CMEs, although originating from E 39 and E 10 respectively, probably only grazed the Earth. Based on our ice-cream cone model (Xue et al. 2005) and CME deflection model (Wang et al. 2004), we find that the CME span angle and deflection are important for the probability of encountering Earth. The large span angles allowed the middle two CMEs hit the Earth, though their source locations were not close to the solar central meridian. The significant deflection made the first CME totally miss the Earth though it also had wide span angle. The deflection may also have made the last CME nearly miss the Earth though it originated close to the disk center. We suggest that, in order to effectively predict whether a CME will encounter the Earth, the factors of the CME source location, the span angle, and the interplanetary deflection should all be taken into account.
We acknowledge the use of the solar data from the LASCO and MDI instruments on board SOHO spacecraft and from the MK4 coronameter at Mauna Loa Solar observatory, and the interplanetary data from Wind spacecraft.We also acknowledge the use of solar event reports compiled by the Space Environment Center of NOAA. We thank Michael L. Kaiser for the comment on type II radio bursts, and thank Ian Richardson and Daniel Berdichevsky for comments on the interplanetary solar wind observations. SOHO is a project of international cooperation between ESA and NASA. This work is supported by the National Natural Science Foundation of China (40525014, 40404014, 40336052, 40336053), the Chinese Academy of Sciences (KZCX3-SW-144 and startup fund), and the Program for New Century Excellent Talents in University (NCET-04-0578). |
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| 26. | Zhou, Guiping, Yuming Wang, and Jingxiu Wang, Coronal mass ejections associated with polar crown filaments, Adv. Space Res., 38(3), 466-469, 2006-03. [(281.1KB)] | Abstract. In the sample of 301 well identified earth-directed halo coronal mass ejections (CMEs) from March 1997 to December 2003, all 21 CMEs associated with polar crown filament (PCF) eruptions are analyzed. Here, the PCFs are viewed as the filaments that partially or totally lie along the boundaries of polar coronal holes, with average length over 100000 , and are intrinsically associated with extended bipole regions (EBRs). The current approach focuses on the CME properties and the flux change in the filament channels. According to the magnetic configurations where the PCFs lie, three classes of PCFs are identified. CMEs present distinguishable velocity distributions associated with each type of PCFs. About 28% of these CMEs present geoeffective. Approximately, 1015 Mx SÀ1 magnetic flux inflow into the filament channel and several times of 1020 Mx flux changed during the course of PCF eruption, which are speculated to trigger the PCF eruptions.
The work is supported by the National Natural Science Foundation of China (G10243003 and G100233050) and the National Key Basic Science Foundation (TG2000078404). |
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| 25. | Shen, Cheng-Long, Yu-Ming Wang, Pin-Zhong Ye, and Shui Wang, Analysis of typical events of coronal holes against the formation of solar energetic particle events, Chinese J. Geophys., 49(3), 2006-03. [ (1.01MB), (1MB)] | Abstract. By comparing and analyzing the solar and interplanetary data of two fast halo coronal mass ejections (CMEs), we find that the CME far away from coronal holes (CHs) caused a great solar energetic particle (SEP) events, but the other one very close to CHs did not cause a major SEP events. It implies that coronal holes might suppress the production of SEPs. Further, by investigating all fast halo CMEs within a distance of 0.2 $R_s$ from CHs during 1997 -- 2003, it is found that none of the CMEs produced a major SEP event. The result proves that the CHs may have effects against the CME producing SEPs. The possible reasons why CHs may prevent CMEs from producing SEPs are briefly addressed finally.
We acknowledge the use of the data from the SOHO, Yohkoh, ACE and GOES spacecraft, and the CH maps from the Kitt Peak Observatory. SOHO is a project of international cooperation between ESA and NASA. This work is supported by the National Natural Science Foundation of China (40525014, 40574063, 40404014, 40336052), the Chinese Academy of Sciences (KZCX3-SW-144 and startup fund), the program for New Century Excellent Talents in University (NCET-04-0578), and the open research program of Key Laboratory for Space Weather, Chinese Academy of Sciences. |
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| 24. | Shen, Chenglong, Yuming Wang*, Pinzhong Ye, and S. Wang, Is there any evident effect of coronal holes on gradual solar energetic particle events, Astrophys. J., 639, 510-515, 2006-01. [(283.4KB)] | Abstract. Gradual solar energetic particle (SEP) events are thought to be produced by shocks, which are usually driven by fast coronal mass ejections (CMEs). The strength and magnetic field configuration of the shock are considered the two most important factors for shock acceleration. Theoretically, both of these factors should be unfavorable for producing SEPs in or near coronal holes (CHs). Meanwhile, CMEs and CHs could impact each other. Thus, to answer the question whether CHs have real effects on the intensities of SEP events produced by CMEs, a statistical study is performed. First, a brightness gradient method is developed to determine CH boundaries. Using this method, CHs can be well identified, eliminating any personal bias. Then 56 front-side fast halo CMEs originating from the western hemisphere during 1997 ­ 2003 are investigated as well as their associated large CHs. It is found that neither CH proximity nor CH relative location manifests any evident effect on the proton peak fluxes of SEP events. The analysis reveals that almost all of the statistical results are significant at no more than one standard deviation. Our results are consistent with the previous conclusion suggested by Kahler that SEP events can be produced in fast solar wind regions and there is no requirement for those associated CMEs to be significantly faster.
We acknowledge the use of the data from the SOHO, Yohkoh, and GOES spacecraft and the CH maps from the Kitt Peak Observatory.We express our heartfelt thanks to the anonymous referee for constructive suggestions and criticisms. SOHO is a project of international cooperation between ESA and NASA. This work is supported by the Chinese Academy of Sciences (KZCX3-SW-144 and startup fund), the National Natural Science Foundation of China (40336052, 40574063, 40404014), and the Program for New Century Excellent Talents in University (NCET-04-0578). |
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| 2005 Top |
| 23. | Wang, Yuming, Chenglong Shen, Pinzhong Ye, and S. Wang, Effect of coronal holes on gradual solar energetic particle events, Proceedings of Solar Wind 11/SOHO 16, , EAS SP PUBL 592, p. 461-464, (Whistler, Canada, June 12-17), 2005-09. [(317.9KB)] | | Abstract. We acknowledge the use of the data from the SOHO, Yohkoh, ACE and GOES spacecraft. This work is supported by the National Natural Science Foundation of China (40336052, 40404014), the Program for New Century Excellent Talents in University (NCET-04-0578), the Chinese Academy of Sciences (KZCX3-SW-144 and startup fund) and the State Ministry of Science and Technology of China (G2000078405). |
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| 22. | 熊明(Xiong, Ming), 郑惠南(Hui-Nan Zheng), 汪毓明(Yu-Ming Wang), 傅向荣(Xiang-Rong Fu), 王水(Shui Wang), and 窦贤康(Xian-Kang Dou), A numerical simulation on the solar-terrestrial transit time of successive CMEs during 4-5 November 1998, Chinese J. Geophys., 48(4), 805-813, 2005-07. [(0.98MB), (382.4KB)] | Abstract. The solar-terrestrial transit process of three successive coronal mass ejections (CMEs) during November 45, 1998 has been investigated numerically in one-dimensional spherical geometry. These CMEs interact with each other while they are propagating in interplanetary space and finally form a “Complex Ejecta”. A Harten’s total variation diminishing (TVD) scheme is applied to solve magnetohydrodynamic (MHD) equations numerically, starting from an ambient solar wind equilibrium, with appropriate dimensionless gravity parameter , plasma beta , and gas polytropic index. The equilibrium is consistent in solar wind speed vr, proton number density Np, and the ratio of proton thermal pressure to magnetic pressure p with the observation of ACE spacecraft at Lagrange point (L1). Merely velocity pulse is introduced in the numerical computation, whose amplitude and duration are determined by observation data of Lasco/C2, GOES, LEAR combined with CME’s “Cone Model” proposed by Michalek et al. The results show that the differences of two shock arrival times (SATs)between the numerical calculation and ACE observation are 3 and 4 hours respectively. Therefore the numerical model proposed in this paper can estimate SAT and rough shock intensity formed by successive CMEs evolving in interplanetary space and suggests a potential application in SAT prediction for space weather.
This work was supported by the National Natural Science Foundation of China (40274050, 40336052, 40404014), the Ministry of Science and Technology of China (NKBRSF G2000078405) and the Chinese Academy of Sciences (KZCX2-SW-136). The authors also acknowledge the use of observation data from SOHO, ACE, GOES spacecrafts and LEAR observatory with gratitude. |
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| 21. | Wang, Yuming, Pinzhong Ye, Guiping Zhou, Shujuan Wang, S. Wang, Yihua Yan, and Jingxiu Wang, The interplanetary responses to the great solar activities in late October 2003, Sol. Phys., 226, 337-357, 2005-05. [(2.84MB)] | Abstract. Based on the observations of the Sun and the interplanetary medium, a series of solar activities in late October 2003 and their consequences are studied comprehensively. Thirteen X-ray flares with importance greater than M-class, six frontside halo coronal mass ejections (CMEs) with span angle larger than 100◦ and three associated eruptions of filament materials are identified by examining lots of solar observations from October 26 to 29. All these flares were associated with type III radio bursts, all the frontside halo CMEs were accompanied by type II or type II-like radio bursts. Particularly, among these activities, two major solar events caused two extraordinary enhancements(exceeding 1000 particles/(cm2 s−1 ster−1 Mev−1) of solar energetic particle (SEP) flux intensity near the Earth, two large ejecta with fast shocks preceding, and two great geomagnetic storms with Dst peak value of −363 and −401 nT, respectively. By using a cross correlation technique and a forcefree cylindrical flux rope model, the October 29 magnetic cloud associated with the largest CME are analyzed, including its orientation and the sign of its helicity. It is found that the helicity of the cloud is negative, contrary to the regular statistical pattern that negative- and positive-helical interplanetary magnetic clouds would be expected to come from northern and southern solar hemisphere. Moreover, the relationship between the orientation of magnetic cloud and associated filament is discussed. In addition, some discussion concerning multiple-magnetic-cloud structures and SEP events is also given.
We acknowledge the use of the data from SOHO, ACE and Wind spacecraft, the Hα data from the YNAO, the radio dynamic spectrum from Huairou/China, Nancay/France, Learmonth Spectrograph/Australia, Hiraiso/Japan and Phoenix-2/Switzerland, and the Dst index fromWorld Data Center.We thank Dr. R. Skoug, Dr. T. Terasawa, Dr. T. Zurbuchen, and Dr. J. Raines for providing the best available solar wind plasma data during October 28–30. We also thank the referee for constructive comments. This work is supported by the Chinese Academy of Sciences (KZCX2-SW-136), the National Natural Science Foundation of China (40404014, 40336052, 40336053), and the State Ministry of Science and Technology of China (G2000078405). |
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| 20. | Wang, Y.*, H. Zheng, S. Wang, and P. Ye, MHD simulation of the formation and propagation of multiple magnetic clouds in the heliosphere, Astron. & Astrophys., 434, 309-316, doi:10.1051/0004-6361:20041423, 2005-04. [(1.11MB), (1.82MB)] | Abstract. A multiple-magnetic-cloud (Multi-MC) structure formed by the overtaking of two successive coronal mass ejections (CMEs) in the heliosphere is studied by using a 2.5-D MHD simulation. This simulation illustrates the process of the formation and propagation of two identical CMEs, which are ejected with speeds of 400 km s−1 and 600 km s−1 respectively and initially separated by 12 h. The results show that it takes ∼18 h for the fast cloud to catch up with the preceding slow one, then the two clouds form a Multi-MC structure that arrives at 1 AU three days later. The fast cloud is slowed down significantly because of the blocking by the preceding slow one. This implies that the travel time of a Multi-MC structure is dominated by the preceding slow cloud. Moreover, most primary observational characteristics of Multi-MC at 1 AU are well represented by the simulation. In addition, by combining observations, theoretical model and the simulation results, differences between Multi-MC and other types of in-situ observed double-flux-rope structure are addressed. A comparison of Multi-MC to coronalmass-ejection cannibalization near Sun is also given.
We acknowledge the use of the data from ACE spacecraft. We also express our thanks to the referee for his constructive suggestions. This work is supported by the Chinese Academy of Sciences (KZCX2-SW-136), the National Natural Science Foundation of China (40404014, 40336052, 40336053 and 40274050), and the
State Ministry of Science and Technology of China (G2000078405). |
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| 19. | Wang, Yuming, Guiping Zhou, Pinzhong Ye, S. Wang, and Jingxiu Wang, Orientation and geoeffectiveness of magnetic clouds as consequences of filament eruptions, in Coronal and Stellar Mass Ejections, Proceedings of IAU symposium No. 226, , edited by K. P. Dere, J. Wang, and Y. Yan, p. 448-453, (Beijing, China, September 13-17, 2004), 2005-03. [(343.5KB)] | | Abstract. We acknowledge the use of the data from the SOHO, Trace and ACE spacecraft. This work is supported by the Chinese Academy of Sciences (KZCX2-SW-136), the National Natural Science Foundation of China (40404014, 40336052, 40336053), and the State Ministry of Science and Technology of China (G2000078405). |
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| 18. | WANG, Yu-Ming and Shui WANG, Comprehensive Studies on Magnetic Clouds in Interplanetary Space and Their Associated Events, J. Grad. School of CAS, 22(2), 248-254, 2005-03. [(940.2KB)] | Abstract. The relationships between the coronal mass ejections (CMEs), interplanetary disturbances and geomagnetic storms are studied, involving the solar source distribution of geoeffective halo CMEs, periodicity of CMEs, X-ray flares, geomagnetic disturbances, threshold of interplanetary parameters in causing geomagnetic storms, etc. As a kind of interplanetary complex structure, multiple magnetic clouds (Multi-MCs) are proposed for the first time, which probably has strong geoeffectiveness. Based on the observations, some primary characteristics of Multi-MCs are summarized. Moreover, the phonomenon of a shock advancing into a preceding magnetic cloud has been investigated as well as its potential geoeffectiveness. A simple theoretical model is developed to estimate the intensity of geomagnetic storms when a shock is entering a preceding cloud.
Supported by National Natural Science Foundation of China (49834030, 40336053), the State Ministry of Science and Technology of China (G2000078405) and the Chinese Academy of Sciences (CKZCX2-SW-136) |
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| 17. | Xue, X. H., Yuming Wang, P. Z. Ye, S. Wang, and M. Xiong, Analysis on the interplanetary causes of the great magnetic storms in solar maximum (2000-2001), Planet. & Space Sci., 53, 443-457, 2005-02. [(2.48MB)] | Abstract. In this paper, we analyze the interplanetary causes of eight great geomagnetic storms ðDstp 200 nTÞ during the solar maximum (2000–2001). The result shows that the interplanetary causes were the intense southward magnetic field and the notable characteristic among the causal mechanism is compression. Six of eight great geomagnetic storms were associated with the compression of southward magnetic field, which can be classified into (1) the compression between ICMEs (2) the compression between ICMEs and interplanetary medium. It suggests that the compressed magnetic field would be more geoeffective. At the same time, we also find that half of all great storms were related to successive halo CMEs, most of which originated from the same active region. The interactions between successive halo CMEs usually can lead to greater geoeffectiveness by enhancing their southwar field Bs interval either in the sheath region of the ejecta or within magnetic clouds (MCs). The types of them included: the compression between the fast speed transient flow and the slow speed background flow, the multiple MCs, besides shock compression. Further, the linear fit of the Dst versus ðVBzÞaðDtÞb gives the weights of VBz and Dt as a ¼ 2:51and b ¼ 0:75; respectively. This may suggest that the compression mechanism, with associated intense Bs; rather than duration, is the main factor in causing a great geomagnetic storm.
We acknowledge the use of the data from ACE, Wind, SOHO spacecraft, the Dst index from World Data Center and Wind MFI website (http://lepmfi.gsfc.nasa.gov/mfi/mag_cloud_pub1.html). We thank the referees for the constructive comments. The research was supported by the Chinese Academy of Sciences (KZCX2-SW-136), the National Natural Science Foundation of China (40404014, 40336052, 40336053) and the State Ministry of Science and Technology of China (G2000078405). |
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| 2004 Top |
| 16. | Wang, Yuming, Chenglong Shen, S. Wang, and Pinzhong Ye, Deflection of coronal mass ejection in the interplanetary medium, Sol. Phys., 222, 329-343, 2004-08. [(249.3KB)] | Abstract. A solar coronal mass ejection (CME) is a large-scale eruption of plasma and magnetic fields from the Sun. It is believed to be the main source of strong interplanetary disturbances that may cause intense geomagnetic storms. However, not all front-side halo CMEs can encounter the Earth and produce geomagnetic storms. The longitude distribution of the Earth-encountered front-side halo CMEs (EFHCMEs) has not only an east­west (E­W) asymmetry (Wang et al., 2002), but also depends on the EFHCMEs' transit speeds from the Sun to 1 AU. The faster the EFHCMEs are, the more westward does their distribution shift, and as a whole, the distribution shifts to the west. Combining the observational results and a simple kinetic analysis, we believe that such E­W asymmetry appearing in the source longitude distribution is due to the deflection of CMEs' propagation in the interplanetary medium. Under the effect of the Parker spiral magnetic field, a fast CME will be blocked by the background solar wind ahead and deflected to the east, whereas a slow CME will be pushed by the following background solar wind and deflected to the west. The deflection angle may be estimated according to the CMEs' transit speed by using a kinetic model. It is shown that slow CMEs can be deflected more easily than fast ones. This is consistent with the observational results obtained by Zhang et al. (2003), that all four Earth-encountered limb CMEs originated from the east. On the other hand, since the most of the EFHCMEs are fast events, the range of the longitude distribution given by the theoretical model is E40 ,W70 , which is well consistent with the observational results (E 40 , W 75 ).
We acknowledge the use of the data from the SOHO, Yohkoh, GOES, ACE and Wind spacecraft. This work is supported by the Chinese Academy of Sciences (KZCX2-SW-136), the National Natural Science Foundation of China (40336052, 40336053), and the State Ministry of Science and Technology of China (G2000078405). |
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| 15. | Guo, Jun, Quan-Ming Lu, Shui Wang, Yu-Ming Wang, and Xian-Kang Dou, Whistler mode waves in collisionless magnetic reconnection, Chinese Phys. Lett., 21(7), 1306-1309, 2004-07. [ (10.56MB)] | |
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| 14. | Wang, Y.-M., P.-Z. Ye, and S. Wang, An interplanetary origin of great geomagnetic storms: Multiple magnetic clouds, Chinese J. Geophys., 47(3), 369-375, 2004-05. [(614KB)] | |
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| 2003 Top |
| 13. | 汪毓明(Wang, Yuming), 叶品中(Pinzhong Ye), and 王水(Shui Wang), Magnetic cloud in interplanetary space (Chinese version), Progress in Astron., 21(4), 301-317, 2003-12. [(5.4MB), (8.43MB)] | |
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| 12. | Lou, Y.-Q., Y.-M. Wang, Z. Fan, S. Wang, and J. Wang, Periodicities in solar coronal mass ejections, Mon. Not. R. Astron. Soc., 345, 809-818, 2003-11. [(6.71MB)] | Abstract. Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during the most recent solar maximum cycle 23 are reported here for the first time using the four year data (February 5, 1999 to February 10, 2003) of the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). In parallel, mid-term quasi-periodicities in solar X-ray flares (class > M5.0) from the Geosynchronous Operational Environment Satellites (GOES) and in daily averages of Ap index for geomagnetic disturbances from the World Data Center (WDC) at the International Association for Geomagnetism and Aeronomy (IAGA) are also examined for the same four-year time span. By Fourier power spectral analyses, the CME data appears to contain significant power peaks at periods of ~ 358 +/- 38, ~ 272 +/- 26, ~ 196+/-13 days and so forth, while except for the ~ 259+/-24-day period, X-ray solar flares of class > M5.0 show the familiar Rieger-type quasi-periods at ~ 157 +/- 11, ~ 122 +/- 5, ~ 98 +/- 3 days and shorter ones until ~ 34 +/- 0:5 days. In the data of daily averages of Ap index, the two significant peaks at periods ~ 273 +/- 26 and ~ 187 +/- 12 days (the latter is most prominent) could imply that CMEs (periods at ~ 272+/-26 and ~ 196 +/- 13 days) may be proportionally correlated with quasi-periodic geomagnetic storm disturbances; at the speculative level, the ~ 138 +/- 6-day period might imply that X-ray flares of class > M5.0 (period at ~ 157+/-11 days) may drive certain types of geomagnetic disturbances; and the ~ 28 +/- 0.2-day periodicity is most likely caused by recurrent high-speed solar winds at the Earth’s magnetosphere. For the same three data sets, we further perform Morlet wavelet analysis to derive period-time contours and identify wavelet power peaks and timescales at the 99 percent confidence level for comparisons. Several conceptual aspects of possible equatorially trapped Rossby-type waves at and beneath the solar photosphere are discussed.
This research (Y.Q.L.) was supported in part by grants from US NSF (AST-9731623) to the University of Chicago, by the ASCI Center for Astrophysical Thermonuclear Flashes at the University of Chicago under Department of Energy contract B341495, by the Special Funds for Major State Basic Science Research Projects of China, by the Collaborative Research Fund from the NSF of China for Outstanding Young Overseas Chinese Scholars (NSFC 10028306) at the National Astronomical Observatories, Chinese Academy of Sciences, and by the Yangtze Endowment from the Ministry of Education through the Tsinghua University. Affliated institutions of Y.Q.L share this contribution. Z.H.F. was supported in part by the NSFC grant 10243006 and the Ministry of Science and Technology of China under grant TG1999075401. |
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| 11. | Wang, Y. M., P. Z. Ye, and S. Wang, Multiple magnetic clouds: Several examples during March - April, 2001, J. Geophys. Res. - Space Phys., 108(A10), 1370, doi:10.1029/2003JA009850, 2003-10. [(1.45MB)] | Abstract. Multiple magnetic cloud (Multi-MC), which is formed by the overtaking of successive coronal mass ejections (CMEs), is a kind of complex structure in interplanetary space. Multi-MC is worthy of notice due to its special properties and potential geoeffectiveness. Using the data from the ACE spacecraft, we identify the three cases of Multi-MC in the period from March to April 2001. Some observational signatures of Multi-MC are concluded: (1) Multi-MC only consists of several magnetic clouds and interacting regions between them; (2) each subcloud in Multi-MC is primarily satisfied with the criteria of isolated magnetic cloud, except that the proton temperature is not as low as that in typical magnetic cloud due to the compression between the subclouds; (3) the speed of solar wind at the rear part of the front subcloud does not continuously decrease, rather increases because of the overtaking of the following subcloud; (4) inside the interacting region between the subclouds, the magnetic field becomes less regular and its strength decreases obviously, and (5) b value increases to a high level in the interacting region. We find out that two of three Multi-MCs are associated with the great geomagnetic storms (Dst À200 nT), which indicate a close relationship between the Multi-MCs and some intense geomagnetic storms. The observational results imply that theMulti-MC is possibly another type of the interplanetary origin of the large geomagnetic storm, though not all of them have geoeffectiveness. Based on the observations from Solar and Heliospheric Observatory (SOHO) and GOES, the solar sources (CMEs) of these Multi-MCs are identified. We suggest that such successive halo CMEs are not required to be originated from a single solar region. Furthermore, the relationship between Multi-MC and complex ejecta is analyzed, and some similarities and differences between them are discussed.
Acknowledgments. We acknowledge the use of the data from ACE, SOHO, GOES spacecraft, and the Dst index from World Data Center. We thank the anonymous referees for the constructive comments. This work is supported by the National Natural Science Foundation of China (49834030), the State Ministry of Science and Technology of China (G2000078405), and the Chinese Academy of Sciences (KZCX2-SW-136). |
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| 10. | Wang, Yuming, C. L. Shen, S. Wang, and P. Z. Ye, An empirical formula relating the geomagnetic storm's intensity to the interplanetary parameters: -VBz and Δt, Geophys. Res. Lett., 30(20), 2039, doi:10.1029/2003GL017901, 2003-10. [(202.6KB)] | Abstract. We statistically study 105 geomagnetic storms with aDst peak value À50 nT during 1998 ­ 2001 to examin the influence of the interplanetary parameters ÀVBz and its duration Át on the intensity of geomagnetic storms. About 33% of the events are associated with intense storms with Dstmin À100 nT. It is found that ÀVBz is much more important than Át for the formation of geomagnetic storms. A stronger ÀVBz can produce a more intense storm, whereas a longer Át can not. A simple empirical formula relating the Dst peak value to ÀVBz and Át is obtained, which shows a good correlation (CC = 0.9528) between the estimate value and the observations. This formula suggests that a compressed Bs field tends to have a more prominent geoeffectiveness. Moreover, we also identify 33 large ÀVBz intervals with ÀVBz > 5 mV/m and Át > 3 hours in the same study interval, and find that they all caused intense storms (Dstmin À100 nT) and 8/9 of the great storms
(Dstmin À200 nT) were due to interplanetary compressed structures.
We acknowledge the use of the data from the ACE and WIND spacecraft and the Dst index from World Data Center. We thank the anonymous referees for the constructive comments. This work is supported by the National Natural Science Foundation of China (49834030), the State Ministry of Science and Technology of China (G2000078405), and the Chinese Academy of Sciences (KZCX2-SW-136). |
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| 9. | Wang, Y. M., P. Z. Ye, S. Wang, and M. Xiong, Theoretical analysis on the geoeffectiveness of a shock overtaking a preceding magnetic cloud, Sol. Phys., 216, 295-310, 2003-09. [(268KB)] | Abstract. The shock compression of the preexisting southward directed magnetic field can enhance a geomagnetic disturbance. A simple theoretical model is proposed to study the geoeffectiveness of a shock overtaking a preceding magnetic cloud. Our aim is to answer theoretically the question how deep the shock enters into the cloud when the event just reaches the maximum geoeffectiveness. The results suggest that the minimum value of Dst decreases initially, then increases again while the shock propagates from the border to the center of the cloud. There is a position where the shock compression of the preceding cloud obtains the maximum geoeffectiveness. In different situations, the position is different. The higher the overtaking shock speed is, the deeper is this position, and the smaller is the corresponding Dstmin . Some shortcomings of this theoretical model are also discussed.
We acknowledge the use of the data from ACE and WIND spacecraft and the Dst index from World Data Center. This work is supported by the National Natural Science Foundation of China (49834030), the State Ministry of Science and Technology of China (G2000078405), and the Chinese Academy of Sciences (KZCX2-SW-136). |
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| 8. | Wang, J., G. Zhou, Y. Wang, and L. Song, Circular polarization in a solar filament, Sol. Phys., 216, 143-157, 2003-09. [(279.5KB)] | |
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| 7. | Wang, Yuming, Comprehensive Studies on Magnetic Clouds in Interplanetary Space and Their Associated Events, Ph.D Dissertation, , University of Science & Technology of China, 2003-09. [(16.56MB),  (119.6KB)] | |
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| 6. | Wang, Y. M., P. Z. Ye, S. Wang, and X. H. Xue, An interplanetary cause of large geomagnetic storms: Fast forward shock overtaking preceding magnetic cloud, Geophys. Res. Lett., 30(13), 1700, doi:10.1029/2002GL016861, 2003-07. [(944.3KB)] | Abstract. In the event that occurred during October 3 ­ 6, 200 at least one magnetosonic wave and one fast forward shock advanced into the preceding magnetic cloud (MC). By using the field and plasma data from the ACE and WIND spacecraft, we analyze the evolution of this event, including the characteristics and changes of the magnetic fields and plasma. At the rear part of the cloud, a large southward magnetic field is caused by a shock compression. The shock intensified a preexisting southward magnetic field. This increased the geoeffectiveness of this event and produced an intense geomagnetic storm with Dst = À175 nT. We also describe another event with a shock overtaking a MC on Nov. 6, 2001. A great geomagnetic storm of intensity Dst = 292 nT resulted. These observations are used to argue that shock compression of magnetic cloud fields is an important interplanetary cause of large geomagnetic storms. Our analyses suggest that the geoeffectiveness is related to the direction of preexisting magnetic fields, the intensity of overtaking shock, and the amount of shock penetration into the preceding MC.
We acknowledge the use of the data from ACE, WIND spacecraft and the Dst index from World Data Center. We thank the anonymous referee very much for the constructive comments and criticisms. This work is supported by the National Natural Science Foundation of China (49834030), the State Ministry of Science and
Technology of China (G2000078405), and the Chinese Academy of Sciences (KZCX2-SW-136). |
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| 5. | 叶品中(Ye, Pin-Zhong) and 汪毓明(Yu-Ming Wang), A study on the Bs events in interplanetary space and the associated CMEs in 2000 (Chinese version), Chinese J. Space Sci., 23, 7-17, 2003-01. [(514.2KB)] | |
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| 2002 Top |
| 4. | Wang, Y. M., S. Wang, and P. Z. Ye, Multiple magnetic clouds in interplanetary space, Sol. Phys., 211, 333-344, 2002-12. [(132KB)] | Abstract. An interplanetary magnetic cloud (MC) is usually considered the byproduct of a coronal mass ejection (CME). Due to the frequent occurrence of CMEs, multiple magnetic clouds (multi-MCs), in which one MC catches up with another, should be a relatively common phenomenon. A simple flux rope model is used to get the primary magnetic field features of multi-MCs. Results indicate that the magnetic field configuration of multi-MCs mainly depends on the magnetic field characteristics of each member of multi-MCs. It may be entirely different in another situation. Moreover, we fit the data from the Wind spacecraft by using this model. Comparing the model with the observations, we verify the existence of multi-MCs, and propose some suggestions for further work.
We acknowledge the use of the data from Wind spacecraft and the `CME catalog'. We also wish to acknowledge the anonymous referee for constructive comments and criticisms. This work is supported by the National Natural Science Foundation of China (49834030), the State Ministry of Science and Technology of China (G2000078405), and the Innovation Engineering Fund of the University of Science and Technology of China. |
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| 3. | Wang, Y. M., P. Z. Ye, S. Wang, G. P. Zhou, and J. X. Wang, A statistical study on the geoeffectiveness of Earth-directed coronal mass ejections from March 1997 to December 2000, J. Geophys. Res. - Space Phys., 107(A11), 1340, doi:10.1029/2002JA009244, 2002-11. [(369.3KB)] | Abstract. We have identified 132 Earth-directed coronal mass ejections (CMEs) based on the observations of the Large Angle Spectroscopic Coronagraph (LASCO) and Extreme Ultraviolet Imaging Telescope (EIT) on board of Solar and Heliospheric observatory (SOHO) from March 1997 to December 2000 and carried out a statistical study on their geoeffectiveness. The following results are obtained: (1) Only 45% of the total 132 Earth-directed halo CMEs caused geomagnetic storms with Kp > 5; (2) The initial sites of these geoeffective halo CMEs are rather symmetrically distributed in the heliographic latitude of the visible solar disc, while asymmetrical in longitude with the majority located in the west side of the central meridian; (3) The frontside halo CMEs accompanied with solar flares (identified from GOES-8 satellite observations) seem to be more geoeffective; (4) Only a weak correlation between the CME projected speed and the transit time is revealed. However, for the severe geomagnetic storms (with Kp > 7), a significant correlation at the confidence level of 99% is found.
We acknowledge the use of the Kp data from WDC, the Wind spacecraft and the ``LASCO CME catalog.'' The CME catalog is generated and maintained by the Center for Solar Physics and Space Weather, The Catholic University of America in cooperation with the Naval Research Laboratory and NASA. We also wish to acknowledge both anonymous referees for constructive comments and criticisms. This work is supported by the National Natural Science Foundation of China (49834030, 19973009) and the State Ministry of Science and Technology of China (G2000078404, 05). |
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| 2. | 宋丽敏(Song, Li-Ming), 张军(Jun Zhang), 杨志良(Zhi-Liang Yang), 汪毓明(Yu-Ming Wang), and 汪景琇(Jing-Xiu Wang), Earth-directed coronal mass ejection (Chinese version), Progress in Astron., 20(1), 33-44, 2002-03. | |
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| 2001 Top |
| 1. | 汪毓明(Wang, Yu-Ming), 叶品中(Pin-Zhong Ye), 高玉芬(Yu-Fen Gao), and 王家龙(Jia-Long Wang), Identification of solar-terrestrial events connected with geomagnetic stroms from the late April to the early may in 1998 (Chinese version), Chinese J. Space Sci., 21, 324-331, 2001-10. | |
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