Imbalance acceleration/escape of energetic particles at interplanetary shocks: effect on spectral steepening

Abstract

Growing multispacecraft networks are broadening the opportunity of measuring energy spectra of energetic particles at interplanetary shocks over three decades or more in energy at the same distance (different from 1 AU) from the Sun. Energetic particles spectra at interplanetary shocks often exhibit a non power law shape, even within two energy decades. We have introduced a 1D transport equation accounting for particle acceleration and escape that allows for escape at all particle energies not only the highest energies and with no free-escape boundary. The diffusion is contributed by self-generated turbulence close to the shock and by pre-existing turbulence far upstream. The momentum spectrum is used to fit the spectra of the 16 GLE events of solar cycle 23. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)