Space Physics Seminar winter-2014

The ring current consists of oppositely drifting ions and electrons with energies of ~ 10 to 200 keV in the same region of the Earth’s magnetosphere that the radiation belts occupy. During geomagnetic storms, these particle populations at ring current energies are significantly increased. Associated with the storm-time ring current is a perturbation magnetic field that distorts the inner magnetospheric magnetic field, thereby affecting radiation-belt dynamics. In this seminar I will discuss briefly early idealizations of ring current formation and then focus on recent advances in understanding ring current dynamics using more realistic self-consistent guiding-center drift and loss simulations. A magnetically and electrically self-consistent treatment of particle transport tends to limit the formation of the ring current as compared to simpler treatments. The ring current intensity and spatial distribution are also significantly affected by variations in the plasma sheet, the major source to the ring current. Comparisons of in-situ magnetic field, proton and electron data, and energetic neutral atom (ENA) intensity with corresponding quantities from our self-consistent ring current simulation model during storm events will be shown. Such comparisons test the ability of our model to characterize the ring current plasma environment and magnetic field and challenge further our understanding of ring current dynamics.