The Distribution of Electromagnetic Power Density in the Ring Current Region

This study analyzes electromagnetic power density (Formula presented.) in the ring current region using MMS data and multi-point analysis method. For the first time, we statistically examine the large-scale distribution characteristics of (Formula presented.) ((Formula presented.) represents statistical results) within the magnetic equatorial plane, revealing a stably particles acceleration region (Formula presented.) on the dawn side and a dynamo region (Formula presented.) on the dusk side. Meanwhile, the corresponding distribution of current density and net charge density are also calculated. In the predawn sector near the acceleration region, a significant accumulation of net negative charges was observed. The dusk-side dynamo region coincides with the net positive charge accumulation. The statistical analysis of electromagnetic power and net charge accumulation implies that the electrostatic field may play an important role in the energy variation of drifting particles, providing new insights into the evolution and dynamics of the ring current.