地球磁尾中重联产生的磁流通管的运动  

Motion of magnetic flux tube produced by reconnection in Earth's magnetotail

作　　者：杨亚芬[1] 陈出新[1] 

机构地区：[1]中国科学院基础等离子体物理重点实验室中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《地球物理学报》2009年第5期1131-1137,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金面上项目(40674092);国家自然科学基金重大项目(40890163);中国科学院重要方向项目(KJCX2-YW-T13-3)资助

摘　　要：本文通过MHD理论研究了细磁流通管在二维静止平衡介质中的运动.用地球磁尾中的一维细丝来表示流通管,通过数值模拟可以得到细丝随时间变化的一些性质.重联产生的细丝磁场比周围磁场偶极性更强,运动时表现出了很强的地向流.结果还显示了阿尔芬波、慢激波等MHD波从磁层的赤道面传播到地球电离层上并部分地反射回来.细丝在电离层上的足点的赤道向运动滞后于赤道面上的地向运动.虽然在模拟中细丝的初始等离子体压强低于周围压强,但是当它开始迅速向地球方向运动时,它的等离子体压强很快上升到与周围压强相当,甚至有时候大于周围压强的值.This paper has studied the motion of a thin magnetic flux tube through a two- dimensional stationary medium that is in equilibrium by an MHD theory. The flux tube is represented as a one-dimensional filament. Some properties of time development of the filament can be obtained from the numerical simulation. The magnetic field line in the filament created by reconnection is more dipolar than the surrounding magnetic field line, and the motion of the filament displays a strong earthward flow. The results show that the propagation of MHD waves such as an Alfven wave and a slow shock from the equatorial plane of magnetosphere to the Earth ionosphere, then partial reflection from the ionosphere. The motion toward the equator of the ionospheric end of the filament is delayed relative to the motion toward Earth in the equatorial plane. Though the plasma pressure in the filament initially is lower than its neighbors, its plasma pressure rose to values comparable to, or sometimes greater than, its neighbors once it started moving earthward fast enough.

关 键 词：等离子体压强 爆发流 细丝 流通管 磁泡 

分 类 号：P353[天文地球—空间物理学]