Comparison of Energetic Electron Intensities Outside and Inside the Radiation Belts

The intensities of energetic electrons (~25 \textendash 800 keV) outside and inside Earth\textquoterights radiation belts are reported using measurements from THEMIS and Van Allen Probes during non-geomagnetic storm periods. Three intervals of current disruption/dipolarization events in August, 2013 were selected for comparison. The following results are obtained. (1) Phase space densities (PSDs) for the equatorially mirroring electron population at three values of the first adiabatic invariant (20, 70, and 200 MeV/G) at the outer radiation belt boundary are found to be one to three orders of magnitude higher than values measured just inside the radiation belt. (2) There is indication that substorm activity leads to PSD increases inside L = 5.5 in less than 1 hr. (3) Evidence for progressive inward transport of enhanced PSDs is found. (4) Reductions and enhancements in the PSDs over L-shells from 3.5 to 6 are found to occur rapidly in ~2 \textendash 3 hrs. These results suggest that (1) continual replenishments are required to maintain high levels of PSD for electrons at these energies, and (2) inward radial transport of these electrons occurs in a fast time scale of a few hrs.