Distribution of Seed Electron Phase Space Density Minima in Earth's Radiation Belts

We conducted a statistical analysis of local phase space density (PSD) minima across a wide energy range (similar to 20 keVs to similar to 10 MeV), using observations from the Van Allen Probes and the Geostationary Operational Environmental Satellite. We identified deepening minima in PSD profiles of multi-MeV (similar to 5% occurrence) and of "seed" electrons (up to 15% occurrence, corresponding to similar to 70-100 s keV) and compared their distribution with a 3D diffusion model using the Versatile Electron Radiation Belts (VERB) code. The comparison of the observed and modeled distributions suggests that the PSD minima of seed electrons are likely associated with hiss waves and the corresponding L-shell dependent electron lifetimes. However, the observed distribution was not fully reproduced by the model, potentially indicating other fast loss mechanisms of seed electrons.