Energetic particle precipitation and the influence on the sub‐ionosphere in the SED plume during a super geomagnetic storm
Energetic particle precipitation and the influence on the sub‐ionosphere in the SED plume during a super geomagnetic storm
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DOI：
10.1029/2011ja016821
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发表时间：
2011-09
影响因子：
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通讯作者：
Z. Yuan;Liqiang Zhao;Y. Xiong;Xiaohua Deng;Jingfang Wang
中科院分区：
文献类型：
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作者：
Z. Yuan;Liqiang Zhao;Y. Xiong;Xiaohua Deng;Jingfang Wang
[1]本文介绍了2001年3月31日地磁暴过程中高能粒子的降水特征及其对风暴增强密度(SED)羽流中次电离层的影响。通过对NOAA16卫星的观测，在二维GPS TEC图上识别的SED羽流区域中，降水电子通量峰位于TEC峰附近。另一方面，在SED羽流的外边界处观测到了高能质子通量的峰值。这些沉淀与注入一系列亚暴引起的环电流(RC)的高能离子/电子有关。当米尔斯通山的数字探空仪位于SED羽流中时，观测到的最低电离图回波频率(Fmin)保持在较高水平。考虑到SED羽流是等离子体层排泄羽流的特征，高能电子的沉淀归因于等离子体层羽流中的RC-ELF HISS相互作用。对一个简单的次电离层模型的计算表明，这些高能电子可以沉淀到次电离层中，并在SED羽流中引起次电离层电离增强。因此，数字探空仪在SED羽流中观测到的fmin保持在较高的水平。因此，本文提供了直接证据，证明了高能RC电子在SED羽流中磁层和次电离层之间的耦合中起着重要的作用。
[1] In this paper, we present precipitation characteristic of energetic particles and the influence on the sub-ionosphere in the storm enhanced density (SED) plume in the event of the geomagnetic storm during March 31, 2001. With observations of the NOAA16 satellite, the peak of precipitating electron flux was located near the TEC peak in region of a SED plume recognized on two-dimensional GPS TEC maps. On the other hand, the peak of precipitating energetic proton flux was observed in the outer boundary of the SED plume. Those precipitations were associated with energetic ions/electrons injected into ring currents (RC) caused by a sequence of substorms. When the Digisonde at Millstone Hill was located in the SED plume, the minimum frequency of ionogram echoes (fmin) was observed to keep a high level. Considering the SED plume as a signature of a plasmaspheric drainage plume, the precipitation of energetic electrons is attributed to the RC-ELF hiss interaction in the plasmaspheric plume. Calculations of a simple sub-ionospheric model demonstrate that those energetic electrons can precipitate into the sub-ionosphere and cause sub-ionospheric ionization enhancements in the SED plume. As a result, the fmin observed by the Digisonde in the SED plume was kept at a high level. Therefore, the paper provides direct evidences that precipitating energetic RC electrons play a significant role in the coupling between magnetosphere and sub-ionosphere in SED plumes.