Response of low-latitude ionosphere to 24 April 2023 geomagnetic storm over the American, African, and Asian–Australian sectors

The responses of the low-latitude ionospheres to the April 2023 geomagnetic storm were investigated using observations from the Global Positioning System-Total Electron Content (GPS-TEC) over the American, African, and Asian–Australian sectors. The TEC distribution from the GPS-TEC receivers across the latitudes was utilized to delineate equatorial ionization anomaly (EIA) structures across the regions. During the main phase of the storm, American EIA crests shifted equatorward with a significant reduction in TEC magnitude (negative ionospheric disturbance), while African crests remained unchanged compared to the quiet period, accompanied with a slight enhancement in TEC magnitude (positive ionospheric disturbance). Conversely, the Asian–Australian EIA crests collapsed to form an extended southern crest with significant enhancement in the TEC magnitude (positive ionospheric disturbance). These longitudinal differences across the sectors depended on couples of physical processes such as storm-time prompt penetration electric field orientation, local storm-time occurrences, variation in inferred E × B drift, storm-time neutral wind, and variations in air composition. However, the geomagnetic storm overall effects on the American sector were ∼3% and ∼7% to the northern and southern crests, respectively. African sector observed ∼6% and 5% toward the northern and southern EIA crests, respectively, while the Asian–Australian sector, witnessed ∼32% effect to the southern EIA crest.