A method to forecast the relativistic electron flux at geostationary orbit

Fluxes of relativistic electrons of the outer radiation belt present a serious threat for on-board electronics of spacecraft orbiting in geosynchronous orbit. This requires development of methods to predict energetic particles in this region of near-Earth space. In this paper, we propose to build a forecast based on the multiple regression (MR) model. Currently, one operating method of relativistic electrons forecast is known. It is displayed on the website of the US National Oceanic and Atmospheric Administration (NOAA). However, it is based on a single predictor, average solar wind speed, and can not accurately predict the sudden changes in particle fluxes during disturbances. In fact, for a successful prediction one must take into account all the complex processes of replenishment of the outer radiation belt due to the acceleration of seed electrons as well as processes of the devastation of the electron flux in the geosynchronous region due to outward adiabatic transport and outward radial diffusion. For this purpose, we have to involve a variety of parameters as predictors measured both at the surface and in the solar wind. The main parameters that correlate with energetic electron fluxes are well known: the solar wind speed, density and dynamic pressure of the interplanetary plasma, the intensity of ULF oscillations in front of the magnetosphere and on the ground, the flow of seed electrons (of hundreds eV energy) at geosynchronous orbit. We have added to them the magnetic field at geostationary orbit and the interplanetary electric field. Coefficients in the MR model equation are calculated from experimental data by the least squares method. The tests showed good results of the proposed forecast model, including prediction of the flux behavior in response to the effect of high-speed solar wind streams on the magnetosphere.