Electrodynamic forcing of the Duskside ionosphere and the super fountain effect during the superstorm of May 10 to 11 2024.

During the extreme space weather event on May 10, 2024, a pronounced super-fountain effect was observed, driven by the prompt penetration electric field (PPEF) and pre-reversal enhancement (PRE) electric field. For this event, the SWARM-A satellite data provided unprecedented insights into the global impact of these electric fields due to its favorable orbit configuration which covered the local dusk sector. Observations revealed significant enhancements in the equatorial fountain, particularly over longitudes between [Formula: see text] E and 55[Formula: see text] W. Notably, this study also detected the first in-situ observational evidence of electron temperature (T[Formula: see text]) increases in the evening equatorial ionosphere during an extreme geomagnetic storm, with T[Formula: see text] enhancements aligning with the super-fountain effect's extent. Additionally, westward electric fields were observed over a nearby longitude along with significant positive storm effects, highlighting the complex and localized nature of impact caused by extreme space weather.