Correlation between the inner edge of outer radiation belt electrons and the innermost plasmapause location

A remarkable correlation between the inner edge of the outer radiation belt electrons and the innermost plasmapause location is demonstrated by using 12 years of measurements of MeV electrons from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) and the Combined Radiation and Release Experiment Satellite (CRRES) during its entire mission ( July 1990 - October 1991). An empirical model of the plasmapause location, Lpp, by O'Brien and Moldwin ( 2003) as well as the measured Lpp during the CRRES mission is used for the comparison. This correlation suggests that the innermost Lpp is the innermost limit of the outer radiation belt penetration. We discuss the possible scenarios that might explain this correlation.