Geosynchronous orbit (GEO, ∼6.6 Earth's radii) is located in the region of the outer radiation. At GEO, hundreds of satellites operate in this region, during the main phase of a high-energy storm, the relativistic electrons rise in count from 10 up to 10 5 (electrons Sr −1 s −1 ) (Sakaguchi et al., 2013). The deep-dielectric charging by relativistic electrons could damage satellites at GEO and poses a risk for space security (Wrenn et al., 2002). According to the statistics of faults, more than 50% failure rate of GEO satellites were caused by the accumulation of high-energy charged particles from March 1992 to April 1994(He et al., 2013. Therefore, the prediction of >2 MeV electron fluxes has important scientific and application value, which is the necessary measure to be taken in advance to reduce the harm of relativistic electrons to space instruments.The sudden acceleration of relativistic electrons is responsible for the increased fluxes. Summers et al. (1998) proposed a model which account for the observed variations in the flux and pitch angle distribution of relativistic electrons during geomagnetic storms. Presently, two types of acceleration mechanisms of relativistic electrons have been proposed: the mechanism of radial diffusion (Li et al., 2001), and the local interaction of wave-particles (Simms et al., 2018). Based on the radial diffusion mechanism, Li et al. (2001) proposed a radial diffusion model that took solar wind parameters and the interplanetary magnetic field as input parameters to predict the relativistic

No abstract