Dartmouth Events

Abstract: Observations of the storm-time ring current have shown that the O+ contribution to the plasma pressure increases significantly during geomagnetic storms, in some cases becoming dominant during the storm main phase.  This is surprising because the direct source of the ring current is the near-earth plasma sheet, and O+ is only rarely dominant there, in terms of either density or pressure.  This talk will address three aspects of the oxygen in the ring current.  First it  will address whether the O+ that contributes to the ring current comes predominantly from the cusp outflow or from the nightside auroral outflow.  Second, it will address how the O+ becomes dominant in the inner magnetosphere.  Finally it will address whether the high charge state oxygen from the  solar wind also plays a role in providing oxygen to the inner magnetosphere.