Extreme Magnetosphere‐Ionosphere‐Thermosphere Responses to the 5 April 2010 Supersubstorm
Extreme Magnetosphere‐Ionosphere‐Thermosphere Responses to the 5 April 2010 Supersubstorm
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DOI：
10.1029/2019ja027654
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
Y. Nishimura;L. Lyons;C. Gabrielse;Nithin Sivadas;E. Donovan;R. Varney;V. Angelopoulos;J. Weygand;M. Conde;S. Zhang
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文献类型：
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作者：
Y. Nishimura;L. Lyons;C. Gabrielse;Nithin Sivadas;E. Donovan;R. Varney;V. Angelopoulos;J. Weygand;M. Conde;S. Zhang
对2010年4月5日的极端亚暴事件（THEMIS AL =-2，700 nT，称为超级亚暴）进行了研究，以检查其驱动过程，负责超级亚暴的极光电流系统，以及磁层-电离层-热层（M-I-T）的响应。行星际冲击产生了冲击极光，但冲击并不是超级亚暴爆发的直接驱动力。相反，一个大的南向国际货币基金组织的冲击加强了增长阶段，大大更大的电离层电流，更快的赤道运动的极光椭圆，更大的电离层电导，更高的磁尾压力比经典亚暴的增长阶段。在超级亚暴开始时的极光增亮很小，但扩张阶段有异常大的极光增亮和电喷流的多步增强。最大的活动是一个非常大的极向边界增强（PBI）和随后的极光流光，开始约20分钟后，亚暴极光开始在一个稳定的向南IMF Bz和升高的动压。这些都与亚暴电流楔（SCW），等离子体片流，相对论粒子注入和降水到D区，总电子含量（TEC），电导和热层中的中性风有关，所有这些都比经典亚暴大得多。SCW并没有延伸到整个夜侧极光活动，但被定位在方位角周围的PBI和流光电离层中的几个100公里。这些结果揭示了局部磁尾重联释放大量能量积累的重要性，这些能量积累可以影响地球同步卫星并产生极端的M-I-T响应。
The extreme substorm event on 5 April 2010 (THEMIS AL = −2,700 nT, called supersubstorm) was investigated to examine its driving processes, the aurora current system responsible for the supersubstorm, and the magnetosphere‐ionosphere‐thermosphere (M‐I‐T) responses. An interplanetary shock created shock aurora, but the shock was not a direct driver of the supersubstorm onset. Instead, the shock with a large southward IMF strengthened the growth phase with substantially larger ionosphere currents, more rapid equatorward motion of the auroral oval, larger ionosphere conductance, and more elevated magnetotail pressure than those for the growth phase of classical substorms. The auroral brightening at the supersubstorm onset was small, but the expansion phase had multistep enhancements of unusually large auroral brightenings and electrojets. The largest activity was an extremely large poleward boundary intensification (PBI) and subsequent auroral streamer, which started ~20 min after the substorm auroral onset during a steady southward IMF Bz and elevated dynamic pressure. Those were associated with a substorm current wedge (SCW), plasma sheet flow, relativistic particle injection and precipitation down to the D‐region, total electron content (TEC), conductance, and neutral wind in the thermosphere, all of which were unusually large compared to classical substorms. The SCW did not extend over the entire nightside auroral activity but was localized azimuthally to a few 100 km in the ionosphere around the PBI and streamer. These results reveal the importance of localized magnetotail reconnection for releasing large energy accumulation that can affect geosynchronous satellites and produce the extreme M‐I‐T responses.