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

[PEM12-07] Super equatorial plasma bubbles associated with storm-induced plasma stream during the 1 December 2023 storm

★Invited Papers

*Guanyi Ma¹, Qingtao Wan¹, Jinghua LI¹, Jiangtao Fan¹, Takashi Maruyama^1,2, Klemens Hocke³, Weizheng Fu⁴, Donghe Zhang⁵, Yang Gao⁶ (1.National Astronomical Observatories, Chinese Academy of Sciences, 2.National Institute of Information and Communications Technology, Tokyo, Japan, 3.Institute of Applied Physics, University of Bern, Bern, Switzerland, 4.Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan, 5.Department of Geophysics, Peking University, Beijing, China, 6.School of Physics and Astronomy, Sun Yat-sen University, Zhuhai, China)

Keywords:Super equatorial plasma bubbles (EPBs), Total electron content (TEC) depletion , TEC bulge, storm-induced plasma stream

This study investigates the ionospheric disturbances triggered by a geomagnetic storm during 1 December 2023, focusing on the development of equatorial plasma bubbles (EPBs) and their latitudinal expansion over China. Utilizing multi-instrument observations, including BeiDou geostationary satellites, Swarm constellation data, and Global Positioning Sysytem (GPS) receivers from the Crustal Movement Observation Network of China (CMONOC), we analyze Total Electron Content (TEC) depletions, electron density variations, and EPB dynamics. The main phase of the geomagnetic storm, initiated by a steep southward turning of the interplanetary magnetic field (IMF Bz) and a sudden storm commencement (SSC) at 0924 UT on 1 December, led to intense solar wind-magnetosphere coupling. Key findings include: (1) Significant TEC depletions (up to 80 TECU) and enhancements (up to 70 TECU) were observed at low-to-mid latitudes (18.6°N–27.1°N), with latitudinal and longitudinal asymmetries linked to storm-driven electric fields and neutral wind effects. (2) Swarm satellite observations revealed electron density depletions extending beyond ±35° magnetic latitude, with hemispheric differences in fluctuation patterns—EPB-like structures dominated the Southern Hemisphere, while density enhancements prevailed in the Northern Hemisphere. (3) EPBs detected by GNSS-derived Rate of TEC Index (ROTI) maps exhibited westward-tilted structures expanding to 44°N, persisting for ~3–4 hours without apparent drift. These EPBs coincided with TEC bulges in mid-latitudes (~30°–45°N), likely driven by storm-induced plasma transport. The results highlight the critical role of geomagnetic storms in redistributing ionospheric plasma and driving mid-latitude irregularities, providing insights into the complex interplay between magnetospheric forcing, thermospheric dynamics, and plasma instabilities in the equatorial F-region during extreme space weather events.