Self-Consistent Theory of a MagnetosphericB-Field Model

A major problem of magnetospheric modeling is the consideration of the plasma in models which describe the magnetic field. The existing magnetospheric vacuum B-field models are incapable of considering the interaction between the plasma and the magnetic field. In these models, the tail field lines are stretched out by artificially inserted infinitesimally thin current layers in order to fit the field line picture to experimental data. Therefore, it is the purpose of this paper to discuss a method to calculate a self-consistent model which satisfies the static MHD force balance equation within the whole magnetosphere. That is, the well known self-consistent theory of the distant tail is extended to the day-side magnetosphere. The total magnetic field consists of the earth's dipole field, the field produced by the Chapman-Ferraro currents, and the field of currents distributed in the magnetosphere. The assumption of an isotropic particle pressure leads to a restrictive condition for possible magnetic field topologies. One can find a two-dimensional equilibrium solution which describes the whole magnetosphere under quiet conditions. With a simplified geometry of the magnetopause, an analytical solution for the magnetic field components has been found. The final result will be a magnetospheric model whose tail field configuration depends on standard parameters, for example the stand-off distance and the dipole tilt angle.