1. 学术报告：Day-to-night transport in the Martian ionosphere 时间：2015年4月7日下午2：30 地点：教学行政楼702/706 报告人：崔峻研究员 单位：国家天文台 摘要：Abstract: The nightisde Martian ionosphere is thought to be contributed by day-to-night transport and electron precipitation, of which the former has not been well studied. Here we evaluate the role of day-to-night transport based on the total electron content (TEC) measurements made by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard Mars Express (MEx). This is accomplished by an examination of the variation of nightside TEC in the time domain rather than the traditional solar zenith angle (SZA) domain. Our analyses here, being constrained to the northern hemisphere where the effects of crustal magnetic fields can be neglected, reveal that day-to-night transport serves as the dominant source for the nightside Martian ionosphere from terminator crossing up to time in darkness, TD, of ~5.3×103s, beyond which it is surpassed by electron precipitation. The observations are compared with predictions from a simplified time-dependent ionosphere model. We conclude that the solid body rotation of Mars is insufficient to account for the observed depletion of nightside TEC but the data could be reasonably reproduced by a zonal electron flow velocity of ~1.9 km s-1.

Qinxiu Li Posted at 2015-04-01 12:13 CST Last modified at 2015-04-01 12:20 CST Link to this poster Top