1. 6月25日学术报告：Comparison between theory and observation of the frequency sweep rates of chorus waves 时间：6月25日（星期一）上午10点 地点：1514会议室 报告人：陶鑫博士 单位：加州理工大学洛杉机分校 Abstract: Theoretical predictions for chorus frequency sweep rates by Helliwell and Trakhtengerts are compared with observations from the THEMIS satellites and a previously published dataset from the Cluster satellites. We first extend the theories to use a general magnetic field model to include the effects of magnetic local time and geomagnetic activity, and then show that both theories give the same dependence of the frequency sweep rate on background plasma parameters. The theoretical scaling of frequency sweep rates are shown to agree very well with observations. We demonstrate that for a given equatorial magnetic field strength, nightside and dawnside chorus waves have higher frequency sweep rates because of the stretching of the magnetic field, while dayside chorus waves have lower frequency sweep rates because of the compression of the field. Increasing geomagnetic activity will enhance the asymmetry by increasing the day-night asymmetry of the background field. The results are important for understanding the generation mechanism of chorus waves.

李勤秀 Posted at 2012-06-21 08:48 CST Last modified at 2012-06-21 08:48 CST Link to this poster Top