The role of inertia of motion of ions in forming a gap and plasmapause.

The role of ion-motion inertia in the formation of the trough and plasmasphere is examined on the basis of the numerical integration of continuity and motion equations for O(+) and H(+) ions in the Lagrangian system of coordinates associated with the dipole geomagnetic field and moving with electromagnetic-drift velocity. It is shown that the formation of the trough and plasmasphere is mainly determined by the filling and emptying of plasma tubes, in which inertia plays the dominant role. The maximum removal of the plasmasphere from the earth in nondisturbed conditions is determined by two characteristic times: the time of plasma-tube filling and the time interval between disturbances.