Persistence of the Long-Duration Daytime TEC Enhancements at Different Longitudinal Sectors During the August 2018 Geomagnetic Storm
Persistence of the Long-Duration Daytime TEC Enhancements at Different Longitudinal Sectors During the August 2018 Geomagnetic Storm
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2018 年 8 月地磁暴期间不同纵向扇区长期白天 TEC 增强的持续性
DOI：
10.1029/2020ja028238
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发表时间：
2020
影响因子：
2.8
通讯作者：
Cui Jun
中科院分区：
文献类型：
--
作者：
Li Qiaoling;Huang Fuqing;Zhong Jiahao;Zhang Ruilong;Kuai Jiawei;Lei Jiuhou;Liu Libo;Ren Dexin;Ma Han;Yoshikawa Akimasa;Hu Lianhuan;Guo Jiapeng;Li Wenbo;Zhou Xu;Cui Jun
在这项研究中，根据北斗地球静止轨道(GEO)卫星和麻省理工学院(MIT)的总电子含量(TECs)，结合电离仪、磁强计和全球紫外线成像仪(GUVI)的测量，研究了2018年8月地磁风暴期间亚洲-澳大利亚、美国和非洲地区的电离层响应。在8月26-29日的风暴期间，中低纬TECs以三个经度扇区的正响应为主。独一无二的是，在恢复阶段，亚洲-澳大利亚、美洲和非洲地区的白天TEC在8月27日至29日表现出超过10个TEC单位(TECU)的大幅增强，当时电离层通常是由于电离层扰动发电机和/或受干扰的热层成分造成的等离子体损耗。扰动垂直等离子体漂移通过太阳风-磁层-电离层耦合和扰动中性成分的合并和竞争对8月26日主恢复阶段和早期恢复阶段不同纵向扇区的白天TEC响应有显著贡献。8月27-29日恢复期赤道东向电喷流和O/N_2均大于平静参考值，表明增强的垂直等离子体漂移和较高的O/N_2对恢复期白天正电离层暴有重要贡献。增强的垂直等离子体漂移不是由与地磁暴有关的Sw-M-I耦合或电离层扰动发电机驱动的。在恢复阶段，不应进行进一步的研究，以探索垂直漂移增强的主要来源。
In this study, the ionospheric responses in the Asian‐Australian, American, and African sectors during the August 2018 geomagnetic storm were investigated based on the Beidou geostationary orbit (GEO) satellite and Massachusetts Institute of Technology (MIT) Madrigal total electron contents (TECs), combined with measurements from ionosondes, magnetometers, and Global Ultraviolet Imager (GUVI). The middle‐ and low‐latitude TECs were dominated by positive responses over the three longitudinal sectors during the storm on 26–29 August. It is unique that daytime TECs at the Asian‐Australian, American, and African sectors displayed large enhancements larger than 10 TEC units (TECu) on 27–29 August, during the recovery phase, when the ionosphere is usually dominated by plasma depletions due to the ionospheric disturbance dynamo and/or disturbed thermospheric compositions. The combination and competition of the disturbed vertical plasma drifts through the solar wind‐magnetosphere‐ionosphere (SW‐M‐I) coupling and disturbed neutral compositions contribute significantly to the daytime TEC responses at different longitudinal sectors on 26 August during the main and early recovery phases. The eastward equatorial electrojet and O/N2during the recovery phase on 27–29 August are larger than the quiet reference, which suggest that the enhanced upward vertical plasma drifts combining with higher O/N2make an important contribution on the daytime positive ionospheric storm during the recovery phase. The enhanced vertical plasma drifts could not be driven by the SW‐M‐I coupling or ionospheric disturbance dynamo associated with the geomagnetic storm. Further studies should be untaken to explore the dominant sources for the enhanced upward vertical drifts during the recovery phase.