Ionospheric Disturbances in Low‐ and Midlatitudes During the Geomagnetic Storm on 26 August 2018
Ionospheric Disturbances in Low‐ and Midlatitudes During the Geomagnetic Storm on 26 August 2018
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DOI：
10.1029/2021ja029879
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
Hyeyeon Chang;H. Kil;K. Sun;Shunrong Zhang;Jiyun Lee
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文献类型：
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作者：
Hyeyeon Chang;H. Kil;K. Sun;Shunrong Zhang;Jiyun Lee
由于形态相似，地磁暴期间中纬度地区的等离子体密度损耗通常用赤道等离子体气泡（EPB）来理解。然而，我们的研究报告的观察结果揭示了当地来源在中纬度地区产生的等离子体损耗。 2018 年 8 月 26 日的地磁风暴期间，国防气象卫星计划和群卫星在赤道地区没有 EPB 的情况下，在亚洲地区中纬度地区检测到等离子体损耗。这一观测结果和日本上空的总电子含量 (TEC) 地图表明，移动电离层扰动 (TID) 是亚洲地区中纬度等离子体损耗的根源。在美国西海岸附近，从 TEC 地图上发现了一条狭窄的 TEC 耗尽带。 TEC耗尽带沿西北-东南方向拉长，以约240 m/s的速度向西移动。 TEC 耗尽带处的 TEC 比环境 TEC 小约 5 TEC 单位 (1016 m−2)。由于该波段仅限于中纬度地区，因此这种现象与 EPB 无关。 TEC 耗尽带的特征与中等规模 TID 的特征一致。对亚洲地区和美国上空 TEC 损耗带的观测表明，当地来源可以在中纬度地区形成等离子体损耗。因此，中纬度不规则性和EPB之间的形态相似性或它们的同时发生并不能提供它们之间联系的确凿证据。
Plasma density depletions at midlatitudes during geomagnetic storms are often understood in terms of equatorial plasma bubbles (EPBs) due to their morphological similarity. However, our study reports the observations that reveal the generation of plasma depletions at midlatitudes by local sources. During the geomagnetic storm on 26 August 2018, the Defense Meteorological Satellite Program and Swarm satellites detected plasma depletions at midlatitudes in the Asian sector in the absence of EPBs in the equatorial region. This observation and the total electron content (TEC) maps over Japan demonstrate that traveling ionospheric disturbances (TIDs) are the sources of midlatitude plasma depletions in the Asian sector. Near the west coast of the United States, the development of a narrow TEC depletion band was identified from TEC maps. The TEC depletion band, which is elongated in the northwest–southeast direction, moves toward the west with a velocity of approximately 240 m/s. The TEC at the TEC depletion band is about 5 TEC units (1016 m−2) smaller than the ambient TEC. As this band is confined to the midlatitudes, this phenomenon is not associated with an EPB. The characteristics of the TEC depletion band are consistent with those of medium‐scale TIDs. Observations in the Asian sector and the TEC depletion band over the United States demonstrate that plasma depletions can develop at midlatitudes by local sources. Therefore, the morphological similarity between midlatitude irregularities and EPBs or their coincident occurrence does not provide corroborating evidence of their connection.