Ion acceleration at dipolarization fronts associated with the interchange instability in Earth's magnetotail
Ion acceleration at dipolarization fronts associated with the interchange instability in Earth's magnetotail
复制标题
与地球磁尾互换不稳定性相关的偶极前沿离子加速
DOI：
10.1007/s11431-019-1505-6
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Sun Chao
中科院分区：
文献类型：
--
作者：
Lu HaoYu;Ge YaSong;Sun Chao
已证实，偶极锋（DF）是地球磁尾交换不稳定性的结果。在本文中，我们使用霍尔 MHD 模型来模拟沿前缘产生 DF 的互换不稳定性的演变。进行测试粒子模拟以研究 DF 处离子加速的物理现象。数值模拟表明，几乎所有粒子都向地球和黎明方向运动，然后漂移到尾部。由于不对称的霍尔电场，黄昏一侧的 DF 反射离子群出现得更早。分布在 DF 后面的黎明-黄昏不对称半圆中的离子往往会被加速到更高的能量 (>13.5 keV)。这些高能粒子最终集中在黎明面。离子在黎明电场的作用下受到有效加速，同时它们通过前部的黎明侧翼向尾部漂移。
It has been confirmed that dipolarization fronts (DFs) are the result of the interchange instability in the Earth’s magnetotail. In this paper, we use a Hall MHD model to simulate the evolution of the interchange instability that produces DFs along the leading edge. A test particle simulation is performed to study the physical phenomenon of ion acceleration at the DF. The numerical simulation indicates that almost all particles move earthward and dawnward and then drift to the tail. The DF-reflected ion population at the duskside appears earlier as a consequence of the asymmetric Hall electric field. Ions that are distributed in a dawn-dusk asymmetric semicircle behind the DF tend to be accelerated to higher energies (>13.5 keV). These high-energy particles eventually concentrate in the dawnside. Ions experience effective acceleration by the dawnward electric field, while they drift through the dawn flank at the front, toward the tail.