A theoretical model for the ring current interaction with the earth's plasmasphere

This paper reports on a theoretical study of the magnetospheric ring current effect on the topside plasmasphere and ionosphere. MHD waves generated by energetic anisotropic protons of the ring current are used as the mechanism for energy transfer to plasmaspheric electrons and ions. Plasmaspheric parameters are calculated in a numerical model for ionospherelasmasphere coupling using a complete system of modelling equations in the 13-moment approximation of the Grad method. The calculations made have shown that the wave mechanism for energy transfer to the thermal plasma ensures its heating in the equatorial plasmasphere to experimentally observed temperatures. The resulting heat flux is able to considerably heat the plasma in the region of the topside ionosphere. It is also shown that the MHD waves present in the plasmasphere substantially influence the height profile of the electron density. The results obtained in this paper lend support to the existence of the experimentally discovered “hot” (or “warm”) zone and to its influence on the underlying ionosphere.