Energetic particle fluxes at heliospheric shocks: evidences of superdiffusion and comparison between analytical and numerical modeling

Abstract Energetic particles fluxes measured by spacecraft in the heliosphere are frequently observed to peak during interplanetary shock crossings, suggesting the shock to be the source of acceleration. It has been shown that the shape of the energetic particle fluxes, upstream and downstream of the shock, is affected by energetic particle transport properties. In this study we make a comparison among a number of shock crossings observed by the ACE spacecraft, and the energetic particle fluxes derived by a test-particle numerical model in the vicinity of a planar shock. We find that observations are in good agreement with a particle density profile obtained in the simulation by assuming superdiffusive transport both upstream and downstream of the shock region.