The ring current and magnetic storms


  • F. V. Coroniti


The ion-cyclotron turbulent ring current precipitation model of magnetic storms is reexamined in light of recent experimental and theoretical developments. The ring current-plasmapause spatial coincidence results from the proton Alfvén layer shielding of the convection electric field. Observations indicate that the dominant ring current precipitation occurs outside the plasmasphere in agreement with recent theories of the high beta, large anisotropy ion cyclotron and electrostatic ion loss cone waves. Hydrogen arc proton precipitation may be caused by parallel electric fields at the equatorward edge of the auroral oval. During the main phase, convection may be both the source and major sink of the asymmetric ring current. During the rapid recovery phase, neutral-wind-induced convection may be the dominant ring current loss process. At this time there is no definitive evidence that ion cyclotron turbulence inside the plasmapause constitutes a major sink for the ring current or generates a SAR arc by electron Landau damping.