Fermi acceleration at relativistic shocks and its radiative signatures

Abstract

The first-order Fermi process at relativistic shocks requires the generation of strong turbulence in the vicinity of the shock front. Recent particle in cell simulations have demonstrated that this mechanism can be studied self-consistently at weakly magnetised shocks. The radiative signature of this first-order Fermi acceleration mechanism is important for models of both the prompt and afterglow emission in gamma-ray bursts. Building on the insight provided by particle in cell simulations, we present possible radiative signatures and show how these can be used as a probe of the local plasma conditions in the source.