时间……….....周三, 2017年10月25日, 下午 04:30-05:50 地点…….........物理大楼 北 415 讲座嘉宾….. ..周晓燕 研究员（UCLA, USA） 讲座题目…… The Auroral-Ionosphere TEC Response to Interplanetary Shocks
讲座摘要：
Collisionless shocks are one of the most fundamental nonlinear phenomena in lab and space plasma. Among shock parameters and features, the most important ones are the shock Mach number and the shock normal plus the IMF precondition in terms of the shocks’ geo-effect. As a visible geo-effect of interplanetary shocks, shock aurora has transient, global, and dynamic significances and represents an acting solar wind – magnetosphere – ionosphere interaction. Inevitably, one of its collateral processes in the ionosphere is the enhancement in the total electron content (TEC). Our recent study revealed an intense, instantaneous, and global GPS/TEC response upon to the arrival of an interplanetary fast-forward shock. The findings showed systematic TEC enhancements of 10-20% in the auroral ionosphere from day to night and a TEC variation that is “duplicating” the shock aurora from the global picture to the small-scale structures in auroral forms, and to their dynamics. However, more details on dayside, which have not been seen in the aurora, were revealed as well. Such as at the shock touch-down location, the TEC increase had an equatorward expansion with a speed at ~45 km/s for the particular event, indicating the compression was penetrating in all the directions, not only in east-west direction, but also south-north. That expansion ended after ~30 sec, suggesting a “braking time” i.e., the time for a new pressure balance to be established. For the same event, the TEC enhancement reached ~60° MLat where the conventional auroral remote sensing cannot reach. Our results implied that it is now possible to monitor the auroral activity and space weather globally using the GPS/TEC data that have some advantages over the existing auroral imaging system: high temporal resolution up to 1 sec and better spatial coverage that is not troubled by the weather, season, and Rayleigh scattering.
图. 地球极光带预报图 [图片来源: NOAA/SEC]
讲座嘉宾介绍：
Xiaoyan Zhou （周晓燕 研究员）
Earth, Planetary and Space Science, University of California, Los Angeles
Ph.D. in Space Physics in 1991 from the Geophysical Institute of The Chinese Academy of Sciences, Beijing, China. Studied magnetic storm forecasting using neural networks.
1994 – 1995, Research visitor at the Institute of Geophysics and Planetary Physics, UCLA, studied magnetotail using ISEE3 data.
1996 – 1997, Associate Researcher at the Geophysical Institute, The Chinese Academy of Sciences, Beijing, China, studied magnetotail and forecasting methods of geomagnetic activity.
1998-2013, Sciences Division, Jet Propulsion Laboratory, California Institute of Technology, studied shock aurora, the solar wind – magnetosphere – ionosphere coupling, interplanetary shocks, heliospheric current sheet and plasma sheet, instruments scientist, mission concept designs.
2014-present Department of Earth, Planetary and Space Sciences, UCLA, studied magnetotail, shock aurora, interplanetary shocks, ionospheric TEC response to interplanetary shocks, the concept and instrument development of imaging dayside and sunlit auroras from balloons using near-infrared (NIR) camera.
