Statistical Analysis of Plasma Bubbles Suppression Over Brazilian Sector

This study presents the first systematic catalog and long‐term statistical analysis of post‐sunset Equatorial Plasma Bubble (EPB) suppression events over northeastern Brazil, based on a 12‐year observational database spanning 2013–2024. The EPB activity was identified using GNSS‐derived Rate of Total Electron Content Index measurements over the São Luís longitudinal sector (40°–50°W). The results demonstrate that EPB suppression occurs under a broad spectrum of geomagnetic conditions, including intense, moderate, and weak geomagnetic storms, as well as during geomagnetically quiet periods (SYM‐H > −30 nT and Kp 3). A clear semiannual variation is observed, with maxima around the equinoxes, coinciding with periods of enhanced geomagnetic storm occurrence. Most suppression events occurred during the descending and ascending phases of the solar cycle. In some cases, suppression effects were observed more than 300 hr after storm onset, suggesting the influence of disturbance dynamo electric fields, modifications in the integrated E‐region Pedersen conductivity, and/or overshielding Prompt Penetration Electric Fields during the evening sector.