Peculiarities in Evolutions of Cosmic Radiation Level after Sudden Decreases

In the analysis of sudden decreases (Forbush Decrease - FD) in the 23rd solar activity cycle we have found that a recovery back to the original level after an FD does not always have, in general, the same time evolution. In this paper we analyze cases where, within an order of magnitude ten hours, an FD is followed by a recovery back to the original level, and then the same decrease as the original one follows, but - according to the satellite data - with no apparent external cause.