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IMF magnitude Bt (Figure 8)

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 ($\log B_t \simeq 0.78$). The P4 (16-32 mHz) events occur much more frequently when the IMF is weaker than 5nT ($\log B_T \leq 0.7$). 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 $P_2, \ldots , P_5$ events at different IMF magnitudes.