A numerical simulation of the geomagnetic sudden commencement: 1. Generation of the field‐aligned current associated with the preliminary impulse
A numerical simulation of the geomagnetic sudden commencement: 1. Generation of the field‐aligned current associated with the preliminary impulse
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DOI：
10.1029/2002ja009407
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发表时间：
2003-12
影响因子：
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通讯作者：
S. Fujita;Takashi Tanaka;T. Kikuchi;K. Fujimoto;K. Hosokawa;M. Itonaga
中科院分区：
文献类型：
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作者：
S. Fujita;Takashi Tanaka;T. Kikuchi;K. Fujimoto;K. Hosokawa;M. Itonaga
[1] 使用太阳风-磁层-电离层耦合系统的 MHD 模型研究了磁层对太阳风脉冲（地磁突然开始）的响应。本文讨论了脉冲发射的第一个信号的传播以及场对准电流的生成，该电流导致地面磁信号被检测为初步脉冲 (PI)。结果表明，PI电流首先在磁层顶被激发为增强的查普曼-费拉罗电流，然后沿着脉冲发射的压缩信号的波前转向磁层。由于等离子体不均匀性，它最终通过模式耦合转换为场对准电流。波前区域中的电流是惯性电流。我们通过数值模拟提出了 Araki [1994] 提出的 PI 模型的定量模型。
[1] The magnetospheric response to a solar wind impulse, a geomagnetic sudden commencement, is studied using an MHD model of the coupled solar wind-magnetosphere-ionosphere system. This paper discusses propagation of the first signal launched by the impulse and generation of the field-aligned current that causes the ground magnetic signal detected as the preliminary impulse (PI). It is revealed that the PI current is first excited as an enhanced Chapman-Ferraro current in the magnetopause and next turns to the magnetosphere along the wavefront of the compressional signal launched by the impulse. It is finally converted to a field-aligned current via mode coupling due to plasma nonuniformity. The current in the wavefront region is an inertia current. We present a quantitative model of the PI model presented by Araki [1994] by using a numerical simulation.