Longitudinal Variability of Pre-midnight Equatorial Plasma Bubbles Under Disturbed Geomagnetic Conditions: The role of Thermospheric Winds

Equatorial plasma bubbles (EPBs) pose significant challenges to trans-ionospheric radio communications, particularly affecting communication and navigation systems. EPB occurrences underscore the importance of evaluating and predicting them in the development of space systems. One critical factor that remains elusive is the influence of geomagnetic activity on EPBs, partly due to a lack of neutral wind measurements. This study aims to address this gap by performing a superposed epoch analysis on key parameters: geomagnetic indices, zonal and meridional neutral winds, and the $\sigma$ index (an indicator of EPB occurrence). Using data collected by the Ionospheric Connection Explorer (ICON) satellite from 2020 to 2022, between 18:00 and 23:00 SLT, our analysis reveals regional differences in EPB behavior. In South America, EPB development is suppressed during the decline of geomagnetic activity, whereas this effect is not detected in other longitudinal sectors. Additionally, we observe a westward shift in zonal winds near the peak of geomagnetic disturbances. These findings contribute to a deeper understanding of EPB dynamics and highlight the regional variability in their response to geomagnetically disturbed conditions.