Evidence of Unusually Strong Equatorial Ionization Anomaly at Three Local Time Sectors During the Mother's Day Geomagnetic Storm On 10–11 May 2024

Abstract

This study uses multiple ground and satellite-based measurements to investigate the extreme ionospheric response to the Mother's Day storm on May 10–11, 2024. Prompt penetration electric field caused a significant enhancement in the ionospheric vertical drift ($\sim$ 95 m/s) and the equatorial electrojet strength ($\sim$ 275 nT) over Jicamarca. These extreme eastward electric field perturbations, along with the large meridional wind, significantly altered the F-region plasma fountain at different local times. The afternoon equatorial ionization anomaly (EIA) not only sustained for an exceptionally long duration ($\sim$ 12 hr) but also expanded spatially over time. The separation between the two peaks of EIA crests exceeded $\sim 48°$ and $\sim 70°$ in the morning and evening sectors, respectively. This study shows, for the first time, that unusually strong EIA can not only develop at different local times but can also sustain for long duration under favorable conditions, which has implications for space weather applications.