Super Equatorial Plasma Bubbles Observed Over South America During the October 10 and 11, 2024 Strong Geomagnetic Storm

On October 10, 2024, the second most intense geomagnetic storm of solar cycle 25 to date took place. This storm was triggered by multiple coronal mass ejections (CMEs) that arrived at Earth from October 7 to 9, causing significant geomagnetic disturbances. The geomagnetic Kp index peaked at its highest level (Kp = 9), indicating a red alert status. This study investigated equatorial plasma bubbles (EPBs) over South America during this geomagnetic storm using ground-based Global Navigation Satellite System (GNSS) rate of total electron content index (ROTI) and Global-scale Observations of the Limb and Disk (GOLD) satellite oxygen atom (OI) 135.6-nm radiance wavelength data. The analysis revealed that the EPBs observed in South America lasted for an unusually long duration of approximately 14 h, from around 23:00 UT (18:00 LT) on October 10 to about 14:00 UT (9:00 LT) on October 11. In addition, these super EPBs extended over a wide latitude range, reaching approximately 35°N and down to 50°S, gradually forming an inverted C-shaped pattern. The observed characteristics of the EPBs are likely associated with changes in solar wind parameters and the effects of the prompt penetration electric field (PPEF).