Complex Ionospheric Fluctuations Over East and Southeast Asia During the May 2024 Super Geomagnetic Storm.

Autor: Sun, Wenjie1,2 (AUTHOR), Li, Guozhu1,2,3 (AUTHOR) gzlee@mail.iggcas.ac.cn, Zhang, Shun‐Rong4 (AUTHOR), Zhao, Biqiang1,2,3 (AUTHOR), Li, Yu5 (AUTHOR), Tariq, M. Arslan6 (AUTHOR), Zhao, Xiukuan2,7 (AUTHOR), Hu, Lianhuan1,2 (AUTHOR), Dai, Guofeng1,2 (AUTHOR), Xie, Haiyong1,2,3 (AUTHOR), Li, Yi1,2 (AUTHOR), Liu, Jianfei1,2 (AUTHOR), Ning, Baiqi1,2 (AUTHOR), Liu, Libo2,3,7 (AUTHOR)
Zdroj: Journal of Geophysical Research. Space Physics. Dec2024, Vol. 129 Issue 12, p1-14. 14p.
Abstrakt: The May 2024 super storm is one of the strongest geomagnetic storms during the past 20 years. One of the most remarkable ionospheric responses to this event over East and Southeast Asia is the complex ionospheric fluctuations following the storm commencement. The fluctuations created multiple oscillations of total electron content (TEC) embedded in the diurnal variation, with amplitudes up to 10 TECu. Along the same latitude, the fluctuations were nearly synchronized over a wide longitude span up to 35°. In the meridional direction, the fluctuations over low latitudes were the most significant and complex, which contained two main components, the poleward extending oscillations originated from the magnetic equator, and the equatorward propagating traveling ionospheric disturbances (TIDs) from high latitudes. The TIDs likely occurred around the globe. The storm‐time interplanetary electric fields penetrating into equatorial latitudes of the ionosphere and the auroral energy input were suggested to drive the poleward extending oscillations and the equatorward TIDs, respectively. Plain Language Summary: The ionospheric responses to strong geomagnetic storms are mainly in the form of global or hemispheric scale plasma density enhancement or suppression, termed as positive or negative ionospheric storms, respectively. Previous studies have also reported fine‐scale ionospheric structures during geomagnetic storms, which were manifested as wavelike fluctuations in TEC. Multiple mechanisms were proposed to be responsible for the TEC fluctuations, including the magnetospheric compression effect, storm‐time penetration electric field, refilling process linked with plasma pressure, and traveling ionospheric disturbances triggered from high latitude and polar regions. During the May 2024 super storm, complex ionospheric fluctuations consisting of two major components, that is, poleward extending fluctuations originated from the magnetic equator and equatorward traveling oscillations from high latitude and polar regions were observed over East and Southeast Asia. It is important to figure out what mechanisms could dominate the generation and evolution of complex fluctuations over specific regions. Based on the TEC continuously measured along dense observational chains, in combination with multiple other types of observations, the characteristics and possible mechanisms of the complex ionospheric fluctuations are investigated. Key Points: Complex ionospheric fluctuations consisting of poleward extending and equatorward traveling disturbances were identified during super geomagnetic stormThe poleward oscillations were synchronized over a wide longitude and driven by multiple penetrations of electric fieldsThe equatorward traveling disturbances likely occurred around the globe that could be due to auroral energy input [ABSTRACT FROM AUTHOR]
Databáze: GreenFILE
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