Enhancements of Radiation Belt High-Energy Electrons Driven by the Magnetospheric Convection

The Earth's outer radiation contains plenty of high-energy electrons. These electron populations exhibit high dynamics, with their fluxes varying by several orders of magnitude during magnetospheric disturbances. The enhancement of these high-energy electrons greatly increases the likelihood of spacecraft malfunction or failure and significantly influences the solar-terrestrial system's energy and mass coupling, highlighting the importance of fully understanding the mechanisms governing these dynamics from both theoretical and practical perspectives. The radial diffusion acceleration driven by ULF waves and local acceleration due to the interaction with whistler mode chorus waves were proposed to explain the enhancement of the radiation belt high-energy electrons. Recent work indicates that the magnetospheric convection, as a key dynamic process within the Earth's magnetosphere, is closely related to the dynamics of high-energy electrons in the radiation belt. Under fast solar wind conditions, the enhanced magnetospheric convection excites intense substorms, which are thought to induce rapid substorm injections of high-energy electrons, leading to relativistic electron enhancements in the outer radiation belt. Case studies and statistical analyses indicate that these injections predominantly enhance electrons in the range of hundreds of keV to 1-2 MeV beyond L ~ 4. Furthermore, in the plasmasphere, where the loss of radiation belt high-energy electrons has been traditionally believed to be dominant due to wave-particle interaction-induced scattering, we have find remarkable MeV electron enhancements. Our analysis shows that this enhancement is related to the magnetospheric convection. The research results are helpful for deepening the understanding of the formation and evolution mechanisms of high-energy electrons in the radiation belt, and also provide an important theoretical basis for further accurately predicting changes in the radiation belt environment and ensuring the safety of spaceflight activities.