Japan Geoscience Union Meeting 2025

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[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM15] Dynamics of Magnetosphere and Ionosphere

Thu. May 29, 2025 1:45 PM - 3:15 PM 302 (International Conference Hall, Makuhari Messe)

convener:Shun Imajo(Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University), Yuka Sato(Nippon Institute of Technology), Akiko Fujimoto(Kyushu Institute of Technology), Kazuhiro Yamamoto(Institute for Space-Earth Environmental Research), Chairperson:Shin-ichiro Oyama(Institute for Space-Earth Environmental Research, Nagoya University), Aoi Nakamizo(Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology)


3:00 PM - 3:15 PM

[PEM15-16] The Characteristics and Possible Mechanisms of the Ionospheric Irregularities during the Geomagnetic storm on 3 March 2024

*Jinghua LI1, Guanyi MA1, Qingtao WAN1, Jiangtao FAN1 (1.National Astronomical Observatories, Chinese Academy of Sciences)

Keywords:ionospheric irregularities, equatorial plasma bubbles, geomagnetic storm

A geomagnetic storm occurred on 3 March 2024, with the minimum SYM-H reaching −127 nT. Although this geomagnetic storm was not very strong, the ionospheric irregularities on this day resulted in a strong ionospheric scintillation. The amplitude scintillation index was larger than 1.0. Global Navigation Satellite System (GNSS) receivers experienced numerous cycle slips and loss of lock of carrier phase over a large longitudinal range of ~30 degrees within ~5 hours in the south of China. Ground-based GNSS receivers, ionosondes and in situ satellite measurements were utilized to analyze the characteristics of the equatorial plasma bubbles (EPBs) during this event. Post-sunset EPBs and morning EPBs were detected by multi instruments. The post-sunset EPBs began before the main phase of the geomagnetic storm and extended to 30 oN in latitude. The EPBs drifted eastward during their evolution. Three uplifts of the ionosphere were observed during the existence of the post sunset EPBs. It is suggested that the three uplifts were respectively related to the pre-reversal enhancement (PRE) of the eastward electric field, the storm-time prompt penetration electric filed (PPEF) and equatorward neutral wind. PRE might play a vital role in the initial generation of the post-sunset EPBs. PPEF and equatorward neutral wind were conductive to the development of the EPBs. As for the morning EPBs, the observations showed they were freshly generated at ~05:00LT, not the persistence of the post sunset EPBs. The morning EPBs drifted westward and survived for ~4 hours. Unlike the post sunset EPBs, they did not cause loss of lock or cycle slip. Accompanying the generation of the morning EPBs, the height of the ionosphere was uplifted once again. The uplift was more obvious at low latitudes. Disturbance dynamo electric fields might contribute to the uplift of the ionosphere and the generation of the morning EPBs. Moreover, large-scale wave structures (LSWS) could potentially serve as the seeding source of the post-sunset and morning EPBs during this event.