It is assumed that Sun-Earth interaction depends on solar wind. In fact, in-tense geomagnetic storms seem to be related to intense interplanetary magnetic field (IMF) with a southern component for a long time [1, 2]. Several papers about geo- magnetic storms [3, 4, 5, 6, 7] have pointed out the reconnection between a southern IMF and the magnetospheric magnetic field as the physical mechanism responsible of Sun-Earth connection. Although several aspects on this mechanism are still open questions, it is accepted that reconnection in the day-side of magnetosphere produces a transference of magnetic flux to the magnetotail [8]. Then energetic particles of solar wind can go into the magnetosphere, along magnetic field lines, yielding an
injection of plasma in the night-side of the magnetosphere.