Interplanetary shock triggering of nightside geomagnetic activity: Substorms, pseudobreakups, and quiescent events
Interplanetary shock triggering of nightside geomagnetic activity: Substorms, pseudobreakups, and quiescent events
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DOI：
10.1029/2000ja003028
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发表时间：
2001-09
影响因子：
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通讯作者：
Xiaoyan Zhou;B. Tsurutani
中科院分区：
文献类型：
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作者：
Xiaoyan Zhou;B. Tsurutani
我们使用风太阳风数据和极地紫外成像数据来研究行星际冲击/压力脉冲的夜侧磁层/磁尾响应。在1997年和1998年在Wind发生的53个行星际激波/压力脉冲事件中，有18个案例可以获得极地近午夜紫外图像。本研究中使用了所有这18个事件。夜侧极光响应可分为亚暴扩展相（SS）（或亚暴进一步增强）事件、假分裂（PB）事件和静止（QE）事件。研究发现，太阳风的先决条件决定了不同极光响应的原因。一个1.5小时的行星际磁场（IMF）Bs的“先决条件”（行星际激波的上游）给出了良好的经验结果。上游IMF在亚暴扩展阶段前强烈向南（占所有事件的44%），PB扩展阶段的IMF Bz为100 nT（占所有事件的39%），静止阶段的IMF纯粹向北（占17%）。IMF Bs预处理的证据被解释为等离子体片加载机制。根据现有的亚暴/PB触发模型，讨论了行星际激波压缩对近地尾的影响。
We use Wind solar wind data and Polar UV imaging data to study the nightside magnetospheric/magnetotail responses to interplanetary shocks/pressure pulses. Of 53 interplanetary shock/pressure pulse events that occurred in 1997 and 1998 at Wind, there are 18 cases where Polar near-midnight UV images are available. All of these 18 events are used in this study. The nightside auroral responses can be classified into three types: substorm expansion phase (SS) (or substorm further intensification) events, pseudobreakup (PB) events, and quiescent (QE) events. It is found that the solar wind preconditions determine the causes of the different auroral responses. A ∼1.5-hour interplanetary magnetic field (IMF) Bs “precondition” (upstream of the interplanetary shock) gives good empirical results. The upstream IMF is strongly southward prior to substorm expansion phase triggerings (44% of all events), the IMF Bz is ∼0 nT for PB triggerings (39% of all events), and the IMF is purely northward for quiescent events (17%). The evidence for IMF Bs preconditioning is interpreted in terms of a plasma sheet loading mechanism. The interplanetary shock compression effects on the near-Earth tail are discussed in light of existing substorm/PB triggering models.