Forecasting the radiation belts

Abstract:

The flux of relativistic electrons in the Earth’s Van Allen belts is highly variable and has been observed to change by several orders of magnitude on a timescale of hours. Predicting these changes and forecasting the state of the radiation belts is becoming more important, as the satellites on which society is becoming increasingly reliant orbit through the radiation belts and can be damaged by energetic electrons. The British Antarctic Survey (BAS) began providing forecasts of the radiation environment in the Van Allen belts on the web in 2012 as part of the EU-FP7 SPACECAST project. In a subsequent project (EU-FP7SPACESTORM), the forecasts were improved and risk indicators and forecasts of spacecraft effects were added in response to stakeholder requests. This approach has recently been extended in collaboration with the UK Met Office in a project funded by ESA.

These forecasts are provided using the BAS Radiation Belt Model (BAS-RBM), a physics-based model which was originally developed as a research tool for understanding the behaviour of the radiation belts. The model includes the effects of wave-particle interactions, radial transport and losses to the magnetopause and atmosphere. We will describe how the model has been adapted for forecasting and discuss some of the challenges this presents. We will show how the inclusion of wave-particle interactions and magnetopause shadowing improve the results, how the boundary conditions for the forecasts are derived and discuss the model accuracy.