Non-steady-state conditions of filling up the geomagnetic trap with superthermal electrons

An approach is presented for the description of superthermal electron diffusion in the plasmasphere in non-steady-state conditions, when the ionospheric source intensity abruptly either increases or decreases. The approach is based on the numerical solution of the kinetic equation averaged over oscillations of trapped electrons between the points of reflection. The solution obtained represents a time-dependent pitch-angular and energy spectrum of superthermal electrons which is averaged over a geomagnetic field line. It has been found that at typical values of electron density, the spectrum formation time of superthermal electrons in the plasmasphere is of the order of tens or hundreds of seconds depending on the parameter of the field line L, which is considerably shorter than the characteristic time of the development of photoelectron source at sunrise. This substantiates the correctness of the stationary approximation. A different situation may arise in the case of a depleted tube, when the time scale changes by 2 to 3 orders. The approach presented may also be applied to the study of the dynamics of electron fluxes, the appearance of which is connected with such non-regular sources as natural or artificial injections