Particle Acceleration by Pickup Process Upstream of Relativistic Shocks

Abstract Particle acceleration at magnetized purely perpendicular relativistic shocks in electron–ion plasmas is studied by means of two-dimensional particle-in-cell simulations. Magnetized with the upstream bulk Lorentz factor γ 1 ≫ are known to emit intense electromagnetic waves from shock front, which induce electrostatic plasma (wakefield) and transverse filamentary structures region via stimulated/induced Raman scattering filamentation instability, respectively. The wakefield filaments inject a fraction incoming particles into particle process, once decoupled flow wakefield, picked up again flow. picked-up accelerated motional electric field. maximum attainable estimated as γ max , e ∼ α 1 3 for electrons ,i}\sim (1+{m}_{e}{\gamma }_{1}/{m}_{i}){\gamma }_{1}^{2}$?> i ( + m stretchy="true">/ stretchy="false">) 2 ions, where α ∼ 10 determined our simulation results. can increase weakly if sufficiently large. This result indicates that highly astrophysical such external gamma-ray bursts be an efficient accelerator.