Extreme Radiation Belt Dropout During the May 2024 Superstorm
Authors
Christos Katsavrias, Sigiava Aminalragia-Giamini, et al.
Abstract
The geomagnetic superstorm in May 2024 represents the most extreme space weather event over the past two decades, offering a unique opportunity to investigate radiation belt electron dynamics under exceptionally strong solar wind driving conditions. Observations from the Arase satellite show that relativistic electron fluxes dropped by several orders of magnitude during the storm main phase. Although magnetopause shadowing and wave-driven losses are established mechanisms, the response of radiation belt electrons to superstorm-level solar wind driving remains poorly constrained. Using the Versatile Electron Radiation Belt model, we present the first physics-based simulation of the May 2024 electron dropout. Utilizing multi-satellite and ground-based observations, we show that the decades-long, widely adopted Kp-driven radial diffusion parameterization fails to represent radial transport under superstorm conditions, substantially misrepresenting both the timing and magnitude of enhanced diffusion relative to observed ultra-low-frequency wave activity. Accurate modeling of the observed extreme dropout requires precise specification of the onset of enhanced radial diffusion, which should coincide with the nearly simultaneous storm-time magnetopause compression. These coupled processes drive the dramatic depletion, followed by scattering from whistler-mode plasma waves.
Year
2026
Venue
AGU Advances Vol. 7 No. 6