Evidence of a Storm‐Induced Plasma Stream Engulfing the Super Bubble During the 1 December 2023 Magnetic Storm

Abstract During the main phase of the 1 December 2023 geomagnetic storm, a superequatorial plasma bubble (EPB) was observed to occur and develop in the East/Southeast Asian sector, causing strong amplitude scintillations from equatorial to mid‐latitudes for about 5 hr. Here, we use total electron content (TEC) and rate of TEC index (ROTI) derived from Global Navigation Satellite System (GNSS) networks to present for the first time the process of a storm‐induced plasma stream (SIPS) engulfing the super EPB. Incorporated with Swarm constellation data and ionograms, a comprehensive analysis reveals that a broad plasma depletion (BPD) within an intensified equatorial ionospheric anomaly (EIA) has preceded the super EPB. The SIPS starts at the end of the main phase from a TEC enhancement over 25°N in the EPB's longitudinal range and develops to a tongue‐like structure embedding the super EPB in the recovery phase of the storm. The whole structure, zonally motionless, exhibits a marked northwestward extension. The SIPS reaches to the northernmost of 50°N in 2 hr and lasts for 8 hr while the superbubble extends to more than 40°N. Our results suggest that the eastward prompt penetration electric field (PPEF) and the prereversal enhancement (PRE) of the eastward electric field synergize to produce the BPD, trigger the super EPB, and mainly cause the plasma bulge at the latitude of the EIA crest. The eastward disturbance dynamo electric field (DDEF) and poleward DDEF together drive the bulge to extend northwestward and form the SIPS engulfing the super EPB.