A numerical simulation of the geomagnetic sudden commencement: 1. Generation of the field-aligned current associated with the preliminary impulse

被引:90
作者
Fujita, S
Tanaka, T
Kikuchi, T
Fujimoto, K
Hosokawa, K
Itonaga, M
机构
[1] Meteorol Coll, Chiba 2770852, Japan
[2] Kyoto Univ, Dept Earth & Planetary Sci, Kyoto 6068502, Japan
[3] Commun Res Labs, Tokyo 1848795, Japan
[4] Yamaguchi Univ, Fac Educ, Yamaguchi 7538513, Japan
关键词
sudden commencement; numerical simulation; preliminary impulse; current system; Tamao-Araki model;
D O I
10.1029/2002JA009407
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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.
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页数:14
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