[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-14] The ionospheric response during the super geomagnetic storm on May 10-11, 2024

*Qingtao Wan¹、Guanyi Ma¹、Guiping Zhou¹、Jinghua Li¹、Jiangtao Fan¹ (1. National Astronomical Observatories, Chinese Academy of Sciences)

キーワード：Geomagnetic storm, Ionosphere, TEC, Physical mechanism

The ionospheric response in the Americas and Asia region was studied during the super geomagnetic storm on May 10-11, 2024, characterized by a minimum Dst of -412nT. GNSS receivers at 100^oW and 100^oE were utilized to study total electron content (TEC). Additionally, electron density profiles from COSMIC occultation, foF2 from ionosondes, vertical ion drift from JULIA MP radar, latitudinal distribution of electron density from Swarm B, and the [O/N2] ratios from TIMED/GUVI were also analyzed. The ionosphere in the Americas exhibited a positive storm, while Asia showed a negative storm. The presence of prompt penetration electric field (PPEF) and the equatorward wind surge were indicated by the increased upward ion drift and the enhancement of equatorial ionospheric anomalies (EIA). The observations of [O/N2] confirm the existence of equatorward expansion of the neutral atmosphere, and the time delay of delta_TEC peak at mid-latitudes was related to the equatorward wind surge. For the first time, we investigated the dominant physical mechanism of ionospheric disturbance at different latitudes by analyzing the variation of delta_TEC peak time with latitude. The estimated speed of disturbance winds was approximately 660 m/s at 50^oN and 150 m/s at 37^oN. The positive storm was likely caused by the disturbance dynamo electric field (DDEF) and wind convergence in both regions during the recovery phase.