Impact of the February 3–4, 2022 geomagnetic storm on ionospheric S4 amplitude scintillation index: Observations and implications

The coincidental loss of 38 out of 49 SpaceX Starlink satellites during their launch on February 3, 2022, concurrent with two moderate geomagnetic storms, opens a unique window into the study of ionospheric irregularities and their potential impacts on Low Earth Orbit assets. This research provides evidence for the first time on the influence of Prompt Penetration Electric (PPE) fields and Disturbance Dynamo (DD) fields on the GNSS S4 amplitude scintillation indices of this particular geomagnetic storm, using observed variations in the distance of Equatorial Ionospheric Anomaly (EIA) crests and the O/N₂ density ratio. By examining observations from the F7/C2 (FORMOSAT-7/COSMIC-2) mission, the NASA/GSFC's OMNI data set, the TIMED/GUVI (Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager) O/N₂ density ratio, and the GIM-TEC (Global Ionosphere Map of Total Electron Content) data, the study uncovers the complex dynamics of storm-induced irregularities and their correlation with suppressed S4 at low latitudes. It reveals the roles of PPE and DD in augmenting and mitigating S4 occurrences, respectively, during different storm phases. These findings contribute to enhancing the understanding of irregularity occurrence rates, scintillation effects, and geomagnetic storms across various longitudinal sectors, thereby providing a case study of changes to the scintillation environment during this moderate but high-profile geomagnetic event.