Instability of the current sheet in the Earth's magnetotail with normal magnetic field
Instability of the current sheet in the Earth's magnetotail with normal magnetic field
复制标题
正常磁场下地球磁尾电流片的不稳定性
DOI：
10.1063/1.4899043
复制
发表时间：
2014
影响因子：
2.2
通讯作者：
A. Bhattacharjee
中科院分区：
文献类型：
--
作者：
N. Bessho;A. Bhattacharjee
用二维全动力学模拟方法研究了地球磁尾电流片的不稳定性。研究了两种磁位形：沿电流片沿着方向具有均匀正磁场的磁位形和正磁场具有空间驼峰的磁位形。后一种配置已经由Sitnov和Schindler [Geophys. Res. Lett. 37，L08102（2010）]作为其中离子撕裂模式可能增长的一种。第一类组态在法向磁场较小时呈现电子撕裂模。第二种类型的配置表现出不撕裂或改变磁场线的拓扑结构的不稳定性。在初始配置中的驼峰可以在非线性区域向地球传播，导致形成一个偶极化前沿。次级磁岛可以在正常磁场非常弱的区域形成。在任何条件下都没有发现离子撕裂不稳定性。
Instability of a current sheet in the Earth's magnetotail has been investigated by two-dimensional fully kinetic simulations. Two types of magnetic configuration have been studied; those with uniform normal magnetic field along the current sheet and those in which the normal magnetic field has a spatial hump. The latter configuration has been proposed by Sitnov and Schindler [Geophys. Res. Lett. 37, L08102 (2010)] as one in which ion tearing modes might grow. The first type of configuration exhibits electron tearing modes when the normal magnetic field is small. The second type of configuration exhibits an instability which does not tear or change the topology of magnetic field lines. The hump in the initial configuration can propagate Earthward in the nonlinear regime, leading to the formation of a dipolarization front. Secondary magnetic islands can form in regions where the normal magnetic field is very weak. Under no conditions do we find the ion tearing instability.