The role of inductive electric fields in shaping the morphology,
asymmetry, and energy content of the storm-time ring current
Abstract
The inductive component of the magnetospheric electric field, which is
associated with the temporal change of magnetic field, provides an
additional means of local plasma energization and transport in addition
to the electrostatic counterpart. This study examines the detailed
response of the inner magnetosphere to inductive electric fields and the
associated electric-driven convection corresponding to different solar
wind conditions. A novel modeling capability is employed to
self-consistently simulate the electromagnetic and plasma environment of
the entire magnetospheric cavity. The explicit separation of the
electric field by source (inductive vs. electrostatic) and subsequent
implementation of inductive effects in the ring current model allow us
to investigate, for the first time, the effect of the inductive electric
field on the kinetics and evolution of the ring current system. The
simulation results presented in this study demonstrate that the
inductive component of the electric field is capable of providing an
additional source for long-lasting plasma drifts, which in turn
significantly alter the trajectories of both thermal and energetic
particles. Such changes in the plasma drift, which arise due to the
inductive electric fields, further reshape the storm-time ring current
morphology and alter the degree of the ring current asymmetry, as well
as the timing and the peak of the ion pressure. The total ion energy is
increasing at a faster rate than the supply of energetic ions to the
ring current, suggesting that the inductive electric field provides
effective and accumulative local energization for the trapped ring
current population without confining additional particles.