Criteria of interplanetary parameters causing intense magnetic storms (Dst of less than -100 nT)

An analysis of ISEE-3 field and plasma data shows that 10 intense magnetic storms that occurred in 1979 were caused by long-duration, large-amplitude (13-30 nT) and negative (less than -10 nT) IMF Bz events associated with interplanetary duskward-electric fields of greater than 5 mV/m. The results suggest that these criteria may be used as predictors of intense storms. A study of opposite polarity (northward) Bz events with the same criteria shows that their occurrence is similar both in number and in their relationship to interplanetary disturbances. The amplitudes of the storms were not found to vary with shock strengths.