Space Weather Effects From Moderate to SevereGeomagnetic Storms in October 2024 Over the LatinAmerican Sector

Abstract

This study presents a detailed case study of the ionospheric impacts of moderate (G2) and severe(G4) geomagnetic storms over the Latin American sector, with particular emphasis on the formation andsuppression of equatorial plasma bubbles (EPBs). The moderate storm of 7–8 October, 2024, presented a rarecase of EPB suppression despite favorable conditions, including a pronounced pre‐reversal enhancement (PRE),with vertical plasma drifts exceeding 40 m/s. Post‐midnight EPBs were observed exclusively in the western sideof the Latin American sector. The observed suppressions may be associated with the influence of meridionalwinds and the presence of an Es layer near the onset time of EPBs. In contrast, the severe storm of 10–11October, 2024, triggered super and long‐lasting EPB across both eastern and western sectors. The enhancementof EPBs during this event is attributed to the combined effects of an undershielding prompt penetration electricfield (PPEF) and disturbance dynamo electric field (DDEF). Moreover, the storm's main phase was marked by apronounced expansion of the Equatorial Ionization Anomaly (EIA) and a significant increase in total electroncontent (TEC), followed by a decrease during the recovery phase. These findings reinforce the importance ofregional and local factors in ionospheric storm‐time responses and suggest the need for further statistical studiesto improve EPB occurrence forecasts.