IMF cone angle $\theta_{BX}$(Figure 6)

In Figure 6, each bin is $10\deg$ wide except for low cone angles where there are fewer data points. The P₄ (16-32 mHz) and P₅ (32-64 mHz) events occur more often when the IMF cone angle $\theta_{BX}$ is low. It is especially clear for the P₅ events. The P₂ events (4-8 mHz) behave oppositely and occur most often when $\theta_{BX}$ is high. The normalized occurrence rate for P₃ appears to be a mixture of the results for higher-frequency and lower-frequency waves.

Figure 6. Normalized occurrence rates for $P_2, \ldots , P_5$ events at different interplanetary magnetic field (IMF) cone angles.