Abstract We investigate the role of plasma pressure and auroral phenomena in the acceleration of relativistic electrons in the outer radiation belt during the intense geomagnetic storm of 1 June 2013. Relativistic electron fluxes, measured by the Van Allen Probes showed a significant depletion during the main phase and a subsequent enhancement during the recovery phase. During the quiet time and the late recovery phase, the slopes of the electron spectra remain nearly unchanged for all L‐shells, indicating the predominance of adiabatic processes, in contrast with the main phase, during which significant changes in the slopes were observed. The maximum plasma pressure increased sharply during the main phase, followed by a rapid decrease during the early recovery phase, and a subsequent, more gradual decrease during the late recovery phase. Simultaneously, the position of the pressure maximum moved toward the Earth, reaching its nearest position at the end of the main phase. Multiple ground‐based data, including the IMAGE magnetometer network, global ionospheric potential maps, and incoherent scatter radars, as well as the AMPERE field‐aligned currents, and auroral energy fluxes from the Ovation Prime model, indicate a correlation between the variations of the outer radiation belt, plasma pressure, and the position and intensity of the auroral oval precipitations, supporting the crucial role of substorm injections in the rebuilding of the outer belt. We assume that the injected seed electron population is further adiabatically accelerated by the recovery of the geomagnetic field, which had been perturbed by an increase in plasma pressure.
Inostroza et al. (2026) studied this question.