A New Model of Outer Belt Electrons for Dielectric Internal Charging (MOBE-DIC)

The outer electron belt poses a significant radiation hazard to spacecraft due to internal charging and dose effects. We present a new user-friendly model to characterise the worst-case environment built on data from the Giove-A spacecraft. We use instrument data based on a novel technique of direct charging current measurements, uncontaminated by protons and unaffected by dead-time, to create the model. The model provides integral or differential electron flux spectra with the following input parameters: percentile 90%, 99% or 100%; L-shell range 3-8; Magnetic Latitude ( B/B₀) range 1-100; Energy range 0.5-3 MeV. Comparisons with other models and independent data sets show that our “Model of Outer Belt Electrons for Dielectric Internal Charging” (MOBE-DIC) provides a sound worst-case specification for mission planners and design engineers. We find that, in medium Earth orbit particularly, MOBE-DIC indicates a harder electron spectrum than either AE9 or FLUMIC.