|To be published Top|
|50.||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., accepted, 2019.|
|49.||Xu, Mengjiao, Chenglong Shen*, Yuming Wang, Bingxian Luo, and Yutian Chi, Importance of Shock Compression in Enhancing ICME’s Geoeffectiveness, Astrophys. J. Lett., accepted, 2019.|
|48.||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, Astrophys. J., 876, 73(12pp), 2019.|
|47.||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.|
|46.||Jiajia Liu, Fuming Wan, Chenglong Shen, Kai Liu, Zonghao Pan, and S. Wang, A SOLAR CORONAL JET EVENT TRIGGERS A CORONAL MASS EJECTION, Astrophys. J., 813, 115, 2015. [(1.71MB), (1.54MB)]|
|45.||L Feng, Y Wang, F Shen, C Shen, B Inhester, L Lu, and W Gan, Why does the apparent mass of a coronal mass ejection increase?, Astrophys. J., 812 (1), 70, 2015.|
|44.||Xudong Sun, Monica Bobra, Todd Hoeksema, Yang Liu, Yan Li, Chenglong Shen, Sebastien Couvidat, Aimee Norton, and George H. Fisher, Why Is the Great Solar Active Region 12192 Flare-Rich But CME-Poor?, Astrophys. J. Lett., 804, L28, 2015.|
|43.||Wang, Yuming, Zhenjun Zhou, Chenglong Shen, Rui Liu, and S. Wan, Investigating plasma motion of magnetic clouds at 1 AU through a velocity-modified cylindrical force-free flux rope model, J. Geophys. Res., 120, 1543 - 1563, 2015. [(5.69MB)]|
|42.||K Liu, Y Wang, J Zhang, X Cheng, R Liu, and C Shen, Extremely Large EUV Late Phase of Solar Flares, Astrophys. J., 802 (1), 35, 2015.|
|41.||Y Wang, Z Zhou, C Shen, R Liu, and S Wang, nvestigating plasma motion of magnetic clouds at 1 AU through a velocity‐modified cylindrical force‐free flux rope model, J. Geophys. Res., 120 (3), 1543-1565, 2015.|
|40.||Rui Liu,, Yuming Wang, and Chenglong Shen, Early Evolution of An Energetic Coronal Mass Ejection And Its Relation to EUV Waves, Astrophys. J., 797, 37, 2014.|
|39.||J Liu, Y Wang, R Liu, Q Zhang, K Liu, C Shen, and S Wang, When and how does a prominence-like jet gain kinetic energy?, Astrophys. J., 782, 94, 2014.|
|38.||Liangwen Shi, Chenglong Shen*, and Yuming Wang, The internplanetary origins of geomagnetic storm with Dstmin<=-50nT in 2007 - 2012 (in chinese), Chinese J. Geophys., 57 (11）, 3822-3833, 2014. [(4.16MB)]|
|37.||Liu-Guan Ding, Gang Li, Yong Jiang, Gui-Ming Le, Cheng-Long Shen, Yu-Ming Wang, Yao Chen, Fei Xu, Bin Gu, and Ya-Nan Zhang, INTERACTION BETWEEN TWO CORONAL MASS EJECTIONS IN THE 2013 MAY 22 LARGE, Astrophys. J. Lett., 793, L35, 2014.|
|36.||Fang Shen, Chenglong Shen, Jie Zhang, Phillip Hess, Yuming Wang, Xueshang Feng, Hongze Cheng, and Yi Yang, Evolution of the 2012 July 12 CME from the Sun to the Earth: Data-Constrained Three-Dimensional MHD Simulations, J. Geophys. Res., 119 (9), 7128-7141, 2014.|
|35.||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., 119(7), 5117 - 5132, 2014.|
|34.||Chenglong Shen, Yuming Wang, Zonghao Pan, Bin Miao, Pinzhong Ye, and S. Wang, Full Halo Coronal Mass Ejections: Arrival at the Earth, J. Geophys. Res., 119(7), 5107 - 5116, 2014. [(1.36MB)]|
|33.||Q Zhang, R Liu, Y Wang, C Shen, K Liu, J Liu, and S Wang, A Prominence Eruption Driven by Flux Feeding from Chromospheric Fibrils, Astrophys. J., 789(2), 133, 2014.|
|32.||Zhenpeng Su, Hui Zhu, Fuliang Xiao, Huinan Zheng, Yuming Wang, Zhaoguo He, Chao Shen, Chenglong Shen, CB Wang, Rui Liu, Min Zhang, Shui Wang, CA Kletzing, WS Kurth, GB Hospodarsky, Harlan E Spence, GD Reeves, HO Funsten, JB Blake, DN Baker, and JR Wygant, Intense duskside lower band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons, J. Geophys. Res., 119(6), 4266-4273, 2014.|
|31.||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., 118, 1-8, 2013. [(776.3KB)]|
|30.||史良文, 申成龙, 汪毓明, and 沈芳, 太阳风扰动传输模式研究进展, 天文学进展, 31, 3, 2013. [(13.16MB)]|
|29.||Yuming Wang, Zhenjun Zhou, Jiajia Liu, Chenglong Shen, and Shui Wang, Dynamic processes of coronal mass ejections in interplanetary space (Chinese Version), Science China：Earth Sciences, 43, 6：934-950, 2013. [(14.89MB)]|
|28.||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, 1-5, 2013. [(437.8KB), (1.32MB)]|
|27.||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. [(2.68MB), (2.68MB)]|
|26.||C. Shen, G. Li, X. Kong, J. Hu, X. D. Sun, L. Ding, Y. Chen, and Yuming Wang, Compound twin coronal mass ejections in the 17 May 2012 GLE event, Astrophys. J., 763, 114, 2013. [(3.65MB)]|
|25.||Yuming Wang, Lijuan Liu, Chenglong Shen, Rui Liu, and S. Wang, Waiting Times of Quasi-homologous Coronal Mass Ejections from Super Active Regions, Astrophys. J., 763, L43, 2013. [(217.7KB)]|
|24.||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, Nature Physics, 8, 923-928,DOI:10.1038/NPHYS2440, 2012. [(221.8KB)]|
|23.||Jiajia Liu, Zhenjun Zhou, Yuming Wang, Rui Liu, Bin Wang, Chijian Liao, Chenglong Shen, Huinan Zheng, Bin Miao, Zhenpeng Su, and S. Wang, Slow Magneto-acoustic Waves Observed above Quiet-Sun Region in a Dark Cavity, Astrophys. J., 758, L26, 2012. [(1.54MB)]|
|22.||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, 2012. [(1.37MB)]|
|21.||Caixia Chen, Yuming Wang, Chenglong Shen, Pinzhong Ye, Jie Zhang, and S. Wang, Statistical Study of Coronal Mass Ejection Source Locations: II. Role of Active Regions in CME Production, J. Geophys. Res., 116, A12108, 2011. [(980.9KB)]|
|20.||Bin Gui, Chenglong Shen, Yuming Wang, Pinzhong Ye, Jiajia Liu, and Shui Wang1, A Quantitative Analysis of the CME Deflections in the Corona, Sol. Phys., 271, 111 - 139, 2011. [(4.34MB), (12.1MB)]|
|Abstract. n 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.|
|19.||Yuming Wang, Caixia Chen, Bin Gui, Chenglong Shen, Pinzhong Ye, and S. Wang, Statistical Study of CME Source Locations: I. Understanding CMEs Viewed in Coronagraphs, J. Geophys. Res., 116, A04104, 2011. [(1.09MB), (1.03MB)]|
|18.||Gui, Bin, Chenglong Shen, Yuming Wang, Pinzhong Ye, and S. Wang, The Forward Modeling Method of CME and Discussion about the Projection Modified Method, Chinese J. Space Sci., 31 (2), 154-164, 2011. [(685.4KB)]|
|Abstract. In this paper, the three-dimension velocity of 21 well-structured Corona Mass Ejections (CMEs) were obtained by Forward modeling based on STEREO-SECCHI observations during 2007-2008. By measuring the height of the projected front in STEREO-A and STEREO-B sky plane and using the projection modified method, modified velocity of these CMEs, which treated as ‘3D’ velocity before, were also obtained. Comparing the 3D velocity gotten from the Forward Modeling method and the modified velocity, we found that: (1) The 3D velocity and the modified velocity are almost the same when angular distance, which is defined as the angle between the line connecting CME source region and Sun center and the line connecting observer and sun center, is greater than 50 degree. (2) When the angular distance is less than 50 degree, the difference is obvious. The Second result shows that the modified method can not be used for the CMEs with angular distance less than 50 degree. We also found that the projected velocity is almost the same as the 3D velocity when the angular distance is greater than 65 degree. This result implies that the CME event with angular distance larger than 65 degree could be treated as a limb event.|
|17.||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,doi:0.1007/s11207-011-9715-8, 2011. [(1.02MB), (3.5MB)]|
|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 kms−1. Then it accelerated continuously
with a positive acceleration of ≈ 7.6 ms−2.
|16.||Quanming Lu, Lican Shan, Chenlong Shen, Tielong Zhang, Yiren Li, and Shui Wang, Velocity distributions of superthermal electrons fitted with a power law function in the magnetosheath: Cluster observations”, J. Geophys. Res., 116, A03224, doi:10.1029/2010JA016118, 2011. [(1.27MB)]|
|Abstract. Satellite observations have revealed that superthermal electrons in space plasma|
generally possess a power law distribution. In this paper, we utilize a power law function
to model the omnidirectional differential fluxes of superthermal electrons observed by
Cluster in the magnetosheath. By assuming an isotropic pitch angle distribution and
performing a nonlinear least squares fitting, we can calculate the index a of the power law
distribution of the superthermal electrons. We found that in the magnetosheath the indices
a of the power law distributions decrease with the increase of wpe/We. It is consistent
with the results of the recent particle‐in‐cell simulations, which described the electron
distributions scattered by enhanced whistler waves. This is the first reported observation
of this relation in space plasma.
|15.||Cheng-Long Shen, Jia Yao, Yu-Ming Wang, Pin-Zhong Ye, Xue-Pu Zhao, and Shui Wang, Influence of Coronal Holes on CMEs in Causing SEP Events, Research in Astronomy and Astrophysics (RAA), 10, 1049-1060, 2010. [(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.|
|14.||Wang, Yuming, Hao Cao, Junhong Chen, Tengfei Zhang, Sijie Yu, Huinan Zheng, Chenglong Shen, Jie Zhang, and S. Wang, Solar LImb Prominence CAtcher & Tracker (SLIPCAT): An Automated System and Its Preliminary Statistical Results, Astrophys. J., 717(2), 973-986, 2010. [(4.82MB)]|
|13.||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., 114, A1010, 2009. [(486.9KB)]|
|12.||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, 2008. [(509.9KB)]|
|Abstract. The behavior of solar energetic particles (SEPs) in a shock magnetic cloud interacting complex structure observed by the Advanced Composition Explorer (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, respectively, propagated within a preceding 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. The comparison of this event with other top SEP events of solar cycle 23 (2000 Bastille Day and 2003 Halloween events) 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 happened not only within the shock MC structure but also after it, probably owing 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 ( Proc. 27th ICRC 8, 3318, 2001b).|
|11.||Chenglong Shen, Studies of Coronal Mass Ejection and its space weather effect, Ph.D Dissertation, , University of Science & Technology of China, 2008. [(19.6MB)]|
|10.||Fuliang Xiao, C. L. Shen, Yuming Wang, Huinan Zheng, and S. Wang, Energetic electron distributions fitted with a kappa-loss-cone function at geosynchronous orbit, J. Geophys. Res., 113, A05203, 2008. [(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 $\theta$ and the spectral index $\kappa$) 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 $\kappa$ basically takes 4, 5 or 6 while the fitting parameters $N$ and $\theta$ 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.
|9.||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(8), 859-867, 2007. [(965.3KB)]|
|8.||XIA Qian (夏倩), SHEN Cheng-Long (申成龙), WANG Yu-Ming (汪毓明), and YE Pin-Zhong (叶品中), The Role of Expansion Velocity of Magnetic Clouds in Flux Rope Model,, Chinese J. Space Sci., 27(4), 271-278, 2007. [(1.64MB)]|
|7.||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 Prediction of Solar Energetic Particle Events, Astrophys. J., 670, 849, 2007. [(2.45MB)]|
|Abstract. Coronal shocks are an important structure but without direct observations in solar and space physics. The strength of shocks plays a key role in shockrelated phenomena, such as radio bursts, SEP generation and so on. This paper will present an improved method of calculating Alfv?en speed and shock strength near the Sun. In the method, observations as many as possible rather than onedimensional global models are used. 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 that a stronger and longer decameter-hectometric (DH) type II radio burst is found during the first event and a short DH type II radio burst during the second event. Particularly, the calculation results explain the observational fact that the slow CME produced a major solar energetic particle (SEP) event while the fast CME did not. Through the comparison between 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, Wind/Waves instrument, GOES satellites, ACE/EPAM instrument, and WSO. SOHO is a project of international cooperation between ESA and NASA. We thank Drs. Yihua Yan and Shujuan Wang for the help in analyzing radio bursts. We are grateful to the referee’s comments and suggestions. This work is supported by the grants from the NSF of China(40574063, 40525014, 40336052, 40404014), the 973 project (2006BC806304), the Chinese academy of Sciences (KZCX3-SW-144 and the startup fund), and the Program for New Century Excellent Talents in University (NCET-04-0578).
|6.||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. [(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).
|5.||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), 629-635, 2006. [(961.5KB)]|
|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.
|4.||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, 2006. [(1.06MB)]|
|Abstract. e 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).
|3.||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, 461-464 (Whistler, Canada, June 12-17), 2005. [(317.9KB)]|
|2.||Wang, Yuming, Chenglong Shen, S. Wang, and Pinzhong Ye, Deflection of coronal mass ejection in the interplanetary medium, Sol. Phys., 222, 329-343, 2004. [(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).
|1.||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, 2003. [(202.6KB)]|
|Abstract. We statistically study 105 geomagnetic storms with a Dst peak value ≤50 nT during 1998–2001 to examine the influence of the interplanetary parameters -VBz and its duration Δt on the intensity of geomagnetic storms. About 33% of the events are associated with intense storms with Dstmin ≤100 nT. It is found that -VBz is much more important than Δt for the formation of geomagnetic storms.|
A stronger -VBz can produce a more intense storm, whereas a longer Δt can not. A simple empirical formula relating the Dst peak value to VBz and t 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 ΔVBz intervals with -VBz > 5 mV/m and Δt > 3 hours in the same study interval, and find that they all caused intense storms (Dstmin ≤100 nT) and 8/9 of the great storms (Dstmin ≤200 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).