[P-EM09] Space Weather and Space Climate

[PEM09-19] A report on the SpaceX storm and the S₄ index response during the 2022 February 3-4 geomagnetic event

*YI DUANN^1,2、Loren C. Chang^1,2、Jann-Yenq Liu^1,2 (1.Department of Space Science and Engineering, National Central University, Taoyuan City 320, Taiwan、2.Center for Astronautical Physics and Engineering, National Central University, Taoyuan City 320, Taiwan)

キーワード：SpaceX, Starlink, FORMOSAT-7/COSMIC-2, Ionospheric scintillation (S4), Disturbance Storm-Time index (Dst)

SpaceX's Starlink satellite mission suffered a major setback during February 3-4, 2022, when at least 40 of the 49 satellites launched failed to reach their intended orbits due to solar storms. In this study, we analyzed data from the FORMOSAT-7/COSMIC-2 (F7/C2) mission and TIMED/GUVI (The Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager) to understand the ionospheric responses and neutral thermosphere expansion during the SpaceX storms. These storms were classified as moderate, with the Disturbance Storm-Time (Dst) index reaching about -61 nT. Our results showed that the ionospheric scintillation (S₄) observed by F7/C2 drifted eastward-upward in groups, and the co-located electron density (Ne) profiles measured by TIMED/GUVI were uplifted and disturbed. The ratio of atomic oxygen to molecular nitrogen (O/N₂) in the F-region also changed, as observed by TIMED/GUVI, contributing to the suppression of S₄ at low latitudes. The physical mechanism behind these observations is thought to be the interaction between the geomagnetic storm and the ionosphere, which leads to changes in the ionosphere's electric fields and ionospheric irregularities. By improving our understanding of this interaction and the relationship between ionospheric irregularity occurrence rates in different longitudinal sectors and geomagnetic storm levels, we can reduce the environmental risks in the ionosphere during vehicle launches and make the ionosphere safer for mission operations in the future.