The earthward plasma-sheet boundary in the magnetospheric tail during magnetic storms

The dynamics of the plasma-sheet inner boundary during a magnetic storm is analyzed using experimental data obtained on board the AMPTE/CCE satellite. It has been shown that, during a magnetic storm, the inner boundary in the near-midnight sector approaches the Earth. With separation from the midnig ht meridian toward morning or evening MLT hours, the distance to the plasma sheet edge increases, and this increase peaks at the recovery phase of a m agnetic storm. The position of the plasma-sheet inner boundary is described quite accurately in the paraboloid model of the magnetospheric magnetic fi eld under assumption of dipole field lines.