IMF北向时磁层顶重联的模拟研究  

Simulation of magnetic reconnection on the magnetopause under northward IMF condition

作　　者：郭九苓[1,2] 沈超[2] 刘振兴[2] 

机构地区：[1]北京大学现代教育技术中心,北京100871 [2]中国科学院空间科学与应用研究中心空间天气学国家重点实验室,北京100080

出　　处：《地球物理学进展》2013年第2期540-544,共5页Progress in Geophysics

基　　金：国家重点基础研究发展计划(2011CB811404);国家自然科学基金(40731054;40974101)资助

摘　　要：本文基于自己开发的全球三维磁层模型,模拟研究了IMF(Interplanetary Magnetic Field)北向时磁层顶重联及磁尾结构.结果发现磁层顶附近存在两种典型的重联过程:一是高纬极尖区IMF与地球磁场的重联,这与空间观测证据和前人的模拟结果是一致的;二是重联后一端在太阳风中另一端与地球相连的磁力线在向磁尾运动中,会发生弯曲、拖曳,在磁尾晨昏侧低纬区域可与尾瓣开放磁力线满足重联条件而再次发生重联.我们认为前一重联会使磁尾等离子片产生与IMF时钟角方向相反的旋转;而后者可重新形成闭合磁力线,可能是LLBL(Low Latitude Boundary Layer)形成的重要原因.We have studied the magnetic reconnection on the magnetopause and tail structure when IMF has a northward component base on a newly developed global MHD simulation model. The results suggest there are two typical merging sites on the magnetopause： tailward of the cusps at high-latitude between IMF and the terrestrial magnetic field, which is consistent with observations and suggestions by other authors; and, when the reconnected IMF with one foot on the Earth is draping over the magnetopause, reeonnection may happen at the tail flanks to form new closed geomagnetic field lines. We argue that the former reconnection would cause the plasma sheet perform a rotation opposite to the IMF clock angle, and the second reconnection may be a key process to the formation of LLBL.

关 键 词：磁层顶 磁尾 晨昏侧 MHD模拟 磁重联 

分 类 号：P318[天文地球—固体地球物理学]