Continuous Detection of Super Plasma Bubbles Over a Broad Longitudinal Span After Sunset During the 25–27 August 2018 Geomagnetic Storm

Abstract

Under disturbed conditions, equatorial plasma bubbles can extend to mid‐latitudes and are then referred to as super plasma bubbles (SPBs). Generally, SPBs develop over several tens of degrees in longitude. Using multi‐satellite in situ observations, rate of TEC index data, and the Prompt Penetration Equatorial Electric Field Model, this study reports that SPBs occurred continuously after sunset over a broad longitudinal span during the geomagnetic storm of 25–27 August 2018. First, SPBs were differentiated from medium‐scale traveling ionospheric disturbances in satellite observations. Then, SPBs were detected sequentially from east to west within 165–285°E, with a maximum combined longitudinal span of ∼73° in a 2‐hr bin. Defense Meteorological Satellite Program (DMSP) F16 observed strong upward ion drifts near the equator inside SPBs, whereas ionosonde data further revealed F‐region uplifts in the longitudinal sectors where SPBs occurred. Correspondingly, geomagnetic indices and prompt penetration electric field simulations showed concurrent or preceding eastward prompt penetration electric fields (PPEFs). Additionally, detrended TEC (dTEC) indicated the presence of large‐scale traveling ionospheric disturbances (LSTIDs) prior to SPB occurrence. These observations and simulations suggest that the sequential occurrence of SPBs may be associated with the combined effects of PPEFs (including convection and overshielding) and LSTIDs.