题目：Using Coordinated Observations in Polarized White Light and Faraday Rotation to Probe the Position, Mass, and Magnetic Field of an Interplanetary Shock

主讲：熊明博士

时间：2012年11月27日（周二）下午2:30-4:30

地点：科学实验楼学术报告厅

内容简介:Interplanetary coronal mass ejections (ICME) can be continuously tracked by direct imaging in visible and radio wavebands of a large portion of the inner heliosphere. Optical brightness as a result of sunlight scattered by interplanetary free electrons depends on the Thomson-scattering process and electron density. Faraday rotation of radio waves from extragalactic pulsars relies on the line-of- sight magnetic componentand electron density. To understand the coordinated white-light and radio observations, we perform forward magnetohydrodynamic modeling of an interplanetary shock and synthesize its remote sensing signatures. The excessive brightness in optics and radio is revealed after deduction of background solar wind contribution. The Thomson scattering efficiency is determined only by a scattering angle, whereas optical brightnessdecrease s with heliocentric distancealmost as. An Earth-directed shock is conspicuously viewed from Lagrangian 5 (L5) point, thus the L5 point is a vantage observation site in space weather. From polarization of excessive optical brightness, the interplanetary positionand plasma massof the main scattering process could be inferred. Then, from Faraday rotation, the localatcould be further estimated. Therefore, simultaneous observations in polarized white light and Faraday rotation could be used to not only detect an ICME but also diagnose its local plasma and magnetic parameters.

熊明，中国科学院空间科学与应用研究中心副研究员。98年9月至07年6月就读于中国科学技术大学地球和空间科学学院，并获空间物理学博士学位。主要研究兴趣包括日冕和行星际的磁流体动力学、日冕物质抛射、太阳风的加速和加热。当前主要从事空间科学背景型号项目—太阳极轨成像望远镜计划（SPORT）科学目标与载荷配置的深化论证、内日球层白光和低频射电的遥感成像等研究。