Wider bins are used in the regions of very weak and very strong IMF in order to obtain better statistics. It is clear that the P5 (32-64 mHz) events strongly favor a small range of IMF magnitudes centered at approximately 6nT (). The P4 (16-32 mHz) events occur much more frequently when the IMF is weaker than 5nT (). For the P3 (8-16 mHz) events, the IMF control is not clear except the high occurrence rate at the weakest Bt bin (Bt < 2.5 nT). The P2 (4-8 mHz) events occur more frequently when the IMF is strong.
|Figure 8. Normalized occurrence rates for events at different IMF magnitudes.|