Radial profile of the magnetospheric plasma pressure extracted from magnetic field data

We have solved the equation for magnetostatic equilibrium for an anisotropi c plasma pressure this equation allows us to determine the pressure profile from a given magnetic field. We have used the magnetic field model of Osta penko and Maltsev [1997], which is a valid representation of the magnetosph eric field for distances ranging from 3 to 10 R-E (Earth radii). This model has as parameters the Dst and Kp indices, the vertical component of the in terplanetary magnetic field, and the solar wind dynamic pressure. The radia l profile of the magnetospheric plasma pressure computed for quiet conditio ns is close to that obtained from direct measurements. The effect of each m odel parameter on the profile has been studied. The total energy content fo r distances from 3 to 10 R-E appears to be controlled primarily by the sola r wind dynamic pressure.