The relationship between the recovery phase of geomagnetic storms and the magnetic clouds

Starting with our elliptical cross-section model for the study of the magnetic topology of magnetic clouds (MCs) in the interplanetary medium, we develop an analytical approach to the behavior of the Dst index at the recovery phase of a geomagnetic storm. Assuming an axially symmetric ring current, we estimate its physical parameters during that recovery phase of the storm-time. We compare the theoretical and measured Dst indexes in two intense geomagnetic storms (Dst