The effect of the March 1991 storm on accumulated dose for selected satellite orbits: CRRES dose models

Three dose models are constructed using direct measurements of dose on the CRRES (Combined Release and Radiation Effects Satellite) in a low-inclination, geosynchronous-transfer orbit. The average model uses data taken over the entire 14 months of the CRRES mission from July 1990 to October 1991. The quiet model uses data from July 1990 to March 1991. The active model uses data from March 1991 to October 1991. The separation of the quiet and active periods is based on the 24 March 1991 solar particle event and subsequent solar wind shock which rearranged the inner magnetosphere radiation populations. The dose models are dose rate averages in grids of L and B/B/sub 0/. A software program (CRRESRAD), developed for the models, allows the calculation of dose behind four shielding thicknesses for any satellite orbit. In the active period, dose acquired in a circular, low-inclination orbit in the slot region is greater than in the quiet period by up to two orders of magnitude, making this region, heretofore thought to be relatively benign, comparable in radiation harshness to the peak of the inner radiation belt. The suitability of the CRRES dose models for evaluating dose in high inclination orbits is also discussed.<
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