CORONAL HOLE ACTIVE-REGION CURRENT SHEET (CHARCS) ASSOCIATION WITH INTENSE INTERPLANETARY AND GEOMAGNETIC-ACTIVITY

Intense geomagnetic storms (Dst less than or equal to -100 nT) have be en associated with interplanetary structures involving large-intensity (B-s greater than or equal to 10 nT) and long-duration (T greater tha n or equal to 3 hours) values of the southward cam component of the IM F. We show that near solar maximum, the solar origin of such structure s seems to be associated with active regions (involving flares and/ o r filament eruptions) occurring close to the streamer belt and to grow ing low-latitude coronal holes. It is also shown that low-latitude cor onal holes had a dual-peak solar cycle distribution during solar cycle 21, similar to that previously reported for the above mentioned inter planetary and geomagnetic phenomena.