Global Response of the MLT and Topside Ionospheric Electron Temperatures to the “Extreme” Geomagnetic Storm of 10‐13 May 2024

This study investigates the global response of the thermal structure of the mesosphere‐lower thermosphere (MLT) region and the topside ionosphere to the extreme geomagnetic storm of May 2024 (Dst nT, SYM‐H nT and ). The MLT temperature response is analyzed using Sounding of the Atmosphere using Broadband Emission Radiometry temperature observations. The thermal response of the topside ionosphere was probed using Swarm satellites' Langmuir probe‐derived electron temperatures . Over latitudes, poleward of N, strong warming was observed around the altitude range of 95–100 km, with peak of 30–35 K. The effects were primarily driven by increased particle precipitation and Joule heating (JH) intensification. The JH was observed to expand equatorward toward latitudes of N, compared to its normal position of N, during magnetically quiet times. At latitudes equatorward of N, the effects were local time dependent, with the dawn sector showing mild warming with peak of 10–15 K, whereas the dusk sector showed almost no effects. Below N latitudes, the observed warming can be attributed to the changes in global circulation patterns brought about by this extreme storm. The topside ionospheric electron temperature showed a much larger response with an enhancement of nearly 2,500 K . These substantial enhancements are observed at latitudes as low as on both sides of the equator. Regarding local time effects, both dawn and dusk sectors showed similar enhancement, though the dusk sector effects were a bit stronger.