A Statistical Study of Warm Plasma Cloak Particles Using Van Allen Probe Data

The Warm Plasma Cloak (WPC) consists of ions in the inner magnetosphere with energies between 10 eV and 1 keV and showing a bidirectional pitch angle distribution of particles. These particles play an important role in wave–particle interactions and in controlling the dayside reconnection rate at the magnetopause. In this study, we present a statistical analysis of WPC (Formula presented.) and (Formula presented.) ions using one orbital precession of the Van Allen Probe-A satellite. The occurrence probability of (Formula presented.) WPC events is found to be 21%, while that of (Formula presented.) WPC events is 40% within the period of January 2013–September 2014. In this work, we observed that dayside WPC events occurred at slightly lower L-shells than night- and dawn-sector WPC events. We also examine the statistics of minimum and maximum energies within the warm plasma range, which reveal bidirectional particle flows. Hence, in this work, we analyzed the spatial variation of the occurrence of WPCs and the minimum and maximum bidirectional energies corresponding to WPC particles observed at (Formula presented.) 7 closer to the plasmapause boundary.