GEOEFFECTIVENESS OF THE HELIOSPHERIC CURRENT SHEET

In the present paper we study the distribution of storm sudden commenc ements (ssc's) and their associated geomagnetic activity with respect to the Earth's crossing of the heliospheric current sheet. We found th at most ssc events occur when the Earth is close to the current sheet. Also, we found that the geoeffectiveness of ssc's seems to be indepen dent of their position with respect to the current sheet. Our results seem to suggest that coronal mass ejections, assumed as the sources of most ssc's, should follow the behavior of ssc's along the solar cycle , i.e., the shock-producing ones should present a bimodal distribution .