Maintaining accurate real-time hindcast and forecast specification of the radiation environment is essential for operators to monitor and mitigate the effects of hazardous radiation on satellite components. The Radiation Belt Forecasting Model and Framework (RBFMF) provides real-time forecasts and hindcasts of the electron radiation belt environment, which are used as inputs for the Satellite Charging Assessment Tool (SatCAT). We evaluated the long-term statistical error and bias of the RBFMF by comparing the 10-hour hindcast of electron phase space densities (PSD) to a multi-mission dataset of PSD observations. We found that, between the years 2016-2018, the RBFMF reproduced the radiation belt environment to within a factor of 1.5. While the error and bias of assimilated observations were found to influence the error and bias of the hindcast, data assimilation resulted in more accurate specification of the radiation belt state than real-time Van Allen Probe observations alone. Furthermore, when real time Van Allen Probe observations were no longer available, the hindcast errors increased by an order of magnitude. This highlights two needs; (i) the development of physics-based modelling incorporated into this framework, and (ii) the need for real-time observations which span the entire outer radiation belt.

We analyzed the contribution of electromagnetic ion cyclotron (EMIC) wave driven electron loss to a flux dropout event in September 2017. The evolution of electron phase space density (PSD) through the dropout showed the formation of a radially peaked PSD profile as electrons were lost at high L*, resembling distributions created by magnetopause shadowing. By comparing 2D Fokker Planck simulations of pitch angle diffusion to the observed change in PSD, we found that the μ and K of electron loss aligned with maximum scattering rates at dropout onset. We conclude that, during this dropout event, EMIC waves produced substantial electron loss. Because pitch angle diffusion occurred on closed drift paths near the last closed drift shell, no radial PSD minimum was observed. Therefore, the radial PSD gradients resembled solely magnetopause shadowing loss, even though the local pitch angle scattering produced electron losses of several orders of magnitude of the PSD.