Solar particle events in the QinetiQ atmospheric radiation model

Models have been embodied within the QinetiQ Atmospheric Radiation Model (QARM) to compute enhancements during major solar particle events and the influence of any concurrent geomagnetic storms that lower the cut-off rigidity. Predictions are compared with available in-flight measurements and extended to give worst case estimates for a number of aircraft routes. It is found that during solar particle events the gradients of particle fluxes with respect to altitude and geomagnetic latitude are so steep that doses and fluences are extremely sensitive to both geomagnetic conditions and the exact route.