The relationship between the plasmapause and outer belt electrons

We quantify the spatial relationship between the plasmapause and outer belt electrons for a 5day period, 15-20 January 2013, by comparing locations of relativistic electron flux peaks to the plasmapause. A peak-finding algorithm is applied to 1.8-7.7MeV relativistic electron flux data. A plasmapause gradient finder is applied to wave-derived electron number densities >10cm(-3). We identify two outer belts. Outer belt 1 is a stable zone of >3MeV electrons located 1-2R(E) inside the plasmapause. Outer belt 2 is a dynamic zone of <3MeV electrons within 0.5R(E) of the moving plasmapause. Electron fluxes earthward of each belt's peak are anticorrelated with cold plasma density. Belt 1 decayed on hiss timescales prior to a disturbance on 17 January and suffered only a modest dropout, perhaps owing to shielding by the plasmasphere. Afterward, the partially depleted belt 1 continued to decay at the initial rate. Belt 2 was emptied out by strong disturbance-time losses but restored within 24h. For global context we use a plasmapause test particle simulation and derive a new plasmaspheric index F-p, the fraction of a circular drift orbit inside the plasmapause. We find that the locally measured plasmapause is (for this event) a good proxy for the globally integrated opportunity for losses in cold plasma. Our analysis of the 15-20 January 2013 time interval confirms that high-energy electron storage rings can persist for weeks or even months if prolonged quiet conditions prevail. This case study must be followed up by more general study (not limited to a 5day period).