Geostationary Orbit Responses to the CME‐Pileup Superstorm on 10 May 2024: Multi‐Satellite Observations

Abstract The extreme geomagnetic storm of 10 May 2024, driven by the interplanetary pileup and merger of multiple coronal mass ejections (CMEs), provides a unique opportunity to investigate the global, local‐time‐resolved response of the geostationary (GEO) environment. Using coordinated observations from GOES‐16 (dayside), GOES‐18 (dawn), and FY‐4B (midnight), we reveal strong magnetic local time (MLT) asymmetry and energy‐dependent behaviors. On the dayside and dawn flank, magnetopause shadowing caused rapid, dispersionless electron dropouts. low‐energy (<100 keV) electron flux enhancements were driven by betatron acceleration and inward radial transport. In contrast, the nightside exhibited a localized dispersionless injection, followed by energy‐dispersed drift echoes for >600 keV electrons and non‐resonant ULF (ultralow frequency) wave modulation for <600 keV electrons. A complete magnetic field reversal was observed at the dawn side, due to larger magnetic shear angles. Geomagnetic indices confirmed the global coherence of the shock impact. These Multi‐satellite observations elucidate differences in magnetospheric driving between compound CME‐Pileup events and isolated storms, advancing our understanding of GEO environmental dynamics during extreme space weather.