Investigations of the hot plasma pressure gradients and the configuration of magnetospheric currents from interball Original Research Article

One of the main aspects of the multi satellite INTERBALL program is connected with the experimental determination of the hot plasma pressure distribution inside the magnetosphere and the solution of the well known problem of the inner magnetosphere substorm onset. The main results of the experimental observations, the structure of high latitude currents and the modeling of the magnetospheric processes are discussed. Observations of particles in a wide energy range from tens of eV to Mev energies give the possibility to construct the full distribution function and to calculate plasma pressure. Quiet time plasma pressure profiles show the regularity and the increase of the pressure with the decrease of the geocentric distance. The observed region of plasma pressure plateau means the existence of nearly zero transverse and field-aligned current regions. The existence of such a region gives the possibility to explain the observed gap between Region 1 and Region 2 currents. Investigations of the fluctuations of the plasma bulk velocity inside the plasma sheet support the existence of plasma sheet turbulence. The existence of plasma sheet turbulence explains the inner magnetosphere substorm onset as only stable before substorm plasma region can become unstable. The introduction of the turbulent transport in the model of the plasma sheet and the theory of the plasma sheet with medium-scale turbulence are discussed