Magnetosphere‐Ionosphere Coupling Between North‐South Propagating Streamers and High‐Speed Earthward Flows
Magnetosphere‐Ionosphere Coupling Between North‐South Propagating Streamers and High‐Speed Earthward Flows
复制标题
南北传播流与高速向地流之间的磁层-电离层耦合
DOI：
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
S. Tian
中科院分区：
文献类型：
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作者：
J. Weygand;J. Bortnik;X. Chu;X. Cao;J. Li;Homayon Aryan;S. Tian
高速向地流和电离层中南北向流之间的磁层-电离层耦合已经讨论了几十年，但到目前为止，还没有人研究过从流开始到结束的耦合的形成。我们调查的磁层电离层耦合的形成和发展，使用THEMIS观测磁尾内的高速向地流动，同步极光全天空图像，和电离层等效电流地图来自地面磁强计测量。我们显示了在南北流光的黎明侧形成向下的场向电流，在黄昏侧形成向上的电流，以及在两个亚暴流光事件的极光椭圆的向极边界到向赤道边缘的场向电流周围的等效电流内的涡流。通过去除背景Birkeland电流系统，我们可以确定电流密度唯一相关的拖缆电流楔，并证明在一个事件的拖缆内的向下和向上的电流近似平衡。此外，我们发现，流光电流楔的纵向尺寸是更短暂的和本地化，并没有改变，而亚暴电流楔是较大的，并扩大在第一部分的亚暴。
The magnetosphere‐ionosphere coupling between the high‐speed earthward flows and the north‐south oriented streamers in the ionosphere has been discussed for decades, but to date, no one has examined the formation of that coupling from the start of the streamer to the end. We investigate the formation and development of the magnetosphere‐ionosphere coupling using THEMIS observations of high‐speed earthward flows within the magnetotail, simultaneous auroral all‐sky images, and ionospheric equivalent current maps derived from ground magnetometer measurements. We show the formation of a downward field‐aligned current on the dawnside of the north‐south streamer and the upward current on the duskside, as well as the vortices within the equivalent currents around the field‐align‐like currents from the poleward boundary to the equatorward edge of the auroral oval for two substorm streamer events. By removing the background Birkeland current system, we can determine the current densities uniquely associated with the streamer current wedge and demonstrate that the downward and upward currents within the streamer are approximately balanced for one event. Furthermore, we find that the longitudinal size of the streamer current wedge is more transient and localized, and does not change, whereas the substorm current wedge is larger and expands during the first part of the substorm.
DOI：
10.1002/2015ja021343
发表时间：
2015-12
期刊：
Journal of Geophysical Research: Space Physics
影响因子：
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作者：
C. Forsyth;I. J. Rae;J. Coxon;M. Freeman;C. Jackman;Jesper Gjerloev;Jesper Gjerloev;A. Fazakerley
通讯作者：
C. Forsyth;I. J. Rae;J. Coxon;M. Freeman;C. Jackman;Jesper Gjerloev;Jesper Gjerloev;A. Fazakerley