Using the empirical magnetospheric magnetic field models of Tsyganenko and Usmanov (TU), we have determined the self-consistent plasma pressure gradients and anisotropies along the midnight meridian in the near-Earth magnetosphere. By “inverting” the magnetic field, we determine what distributions of an anisotropic plasma, confined within the specified magnetic field configuration, are consistent with the magnetohydrostatic equilibrium condition, J × B = ∇ · P. The TU model, parameterized for different levels of geomagnetic activity by the Kp index, provided the magnetic field values from which J × B was numerically evaluated. A best fit solution was found that minimized the average difference between J × B and ∇ · P along an entire flux tube. Unlike previous semi-empirical models, the TU models contain magnetic stresses that can be balanced by a nearly isotropic plasma pressure with a reasonable radial gradient at the equator.
Geophysical Research Letters
American Geophysical Union
Digital Object Identifier (DOI)
Spence, Harlan E.; Kivelson, Margaret G.; and Walker, Raymond J., "Static magnetic field models consistent with nearly isotropic plasma pressure" (1987). Geophysical Research Letters. 300.
Copyright 1987 by the American Geophysical Union.