Modelling the dynamics of fluxes of electrons with energies 30-300 keV in geostationary orbit

A model of the dynamics of electrons with energies 30 to 300 keV along a geostationary orbit was constructed. The purpose of the model was a diagnosis or prediction of the state of the medium at a specific moment in time on the basis of input parameters (geophysical and heliophysical indices). In this model the electron flux I with energy E acting on a satellite in a geostationary orbit at a specific moment in universal time can be described by three components: (1) asymmetry of drift shells of electrons in a 'stationary' magnetosphere; (2) adiabatic change in fluxes of electrons associated with slow deformation of drift shells with a change in solar wind parameters; and (3) nonadiabatic changes in electron fluxes occurring during a substorm and 'injection' events. The model was used in an analysis of data for the period 10 Mar. to 16 Jun., 1986. Measurements were made in six channels in the energy range 30 to 300 keV on three satellites situated approximately uniformly along a geostationary orbit. Each of the satellites carried identical particle spectrometers. An analysis of the spectra of variations gives the basis for representation of the change in electron fluxes in the course of a 24 hour period in the form of an expansion into a Fourier series. As an illustration, the results of use of the model for a retrospective prediction of the mean hourly fluxes of electrons in a geostationary orbit are given for a day with average magnetic activity during which several substorms were observed.