Specifying High Altitude Electrons Using Low-Altitude LEO Systems: Updates to the SHELLS Model

Abstract

We describe a new version of the SHELLS model, which specifies the outer electron belt environment as observed by the Van Allen Probes using the Kp Index and data from Polar-orbiting Operational Environmental Satellites and the Meteorological Operational satellites as inputs. The updated model combines the radial, angular and energy dependence into a single neural network, allowing for specification of the electron environment for a set of user input energy, L-shell and Bmirror values. We demonstrate that the model can accurately reproduce the outer electron radiation belt dynamics using both out-of-sample data from the Van Allen Probes and measurements from the Combined X-ray Dosimeter instrument on GPS. This updated model will provide valuable characterization of the internal charging hazard for non-GEO orbits, particularly in the post-Van Allen Probes era.