Superposed Epoch Analyses of electron-driven and proton-driven magnetic dips

In this study, we use the Van Allen Probes data statistically to investigate the features of magnetic dips by the means of superposed epoch analysis. Based on the different max values of electron and proton plasma betas, we categorize the dips into two types: electron-driven dips and proton-driven dips. Superposed epoch analysis on two types of magnetic dips suggests the correlation between the magnetic fluctuations and plasma betas. Moreover, the occurrence of the butterfly distributions of relativistic electrons driven by the magnetic dips is confirmed by the statistical results. Our results reveal the statistical characteristics of magnetic dips and build up the relationship among the magnetic fluctuations and several parameters, indicating the potentially important role of magnetic dips in the dynamics of the inner magnetosphere.