4. Shortcomings of present day radiation belt models

The old NASA AP-8 and AE-8 radiation belt models (6) are still the de facto standards for engineering applications. This is mainly due to the fact that up to now they are the only models that completely cover the region of the radiation belts, and have a wide energy range for both protons and electrons. It should be noted that a considerable part of the range of the NASA models was achieved by extrapolation.

The NASA models are static and are in principle only valid for the period when the data for the models were obtained (16). In view of the dynamic characteristics of the radiation belts outlined in Section 2.4, it is clear that correspondingly dynamic models are needed for accurate predictions of mission fluences and doses. Several efforts are under way to include dynamic behaviour in new radiation belt models, but up to now no models are available that duplicate the spatial and energy range of the NASA models. In order to achieve this, high quality data are needed from different locations in the magnetosphere, covering long time periods and with high resolution in energy, direction and time. Simple radiation monitors could easily be installed on commercial satellites, which would help the continuous upgrading needed for truly dynamic radiation belt models. However, as long as not all features of the radiation belts are fully understood or adequately modelled, high quality data are indispensable.

Back to "Overview of radiation belt modeling"