Particle acceleration at ultrarelativistic, perpendicular shock fronts

Abstract

Using an eigenfunction expansion to solve the transport equation, complemented by Monte-Carlo simulations, we show that ultrarelativistic shocks can be effective particle accelerators even when they fail to produce large amplitude turbulence in the downstream plasma. This finding contradicts the widely held belief that a uniform downstream magnetic field perpendicular to the shock normal inhibits acceleration by the first order Fermi process. In the ultrarelativistic limit, we find a stationary power-law particle spectrum of index s=4.17 for these shocks, close to that predicted for a strictly parallel shock.

9 pages, 6 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society

References in corpus (8)

• Long Term Evolution of Magnetic Turbulence in Relativistic Collisionless Shocks: Electron-Positron Plasmas
• Magnetic field evolution in relativistic unmagnetized collisionless shocks
• On Fermi acceleration and MHD-instabilities at ultra-relativistic magnetized shock waves
• Constraints on particle acceleration sites in the Crab Nebula from relativistic MHD simulations
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• The implications of TeV detected GRB afterglows for acceleration at relativistic shocks
• Microphysics of Relativistic Collisionless Electron-ion-positron Shocks
• Electron acceleration at pulsar wind termination shocks

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• Hadronic emission from the environment of the Crab Pulsar Wind Nebula by re-accelerated particles
• Particle acceleration to PeV energies in Pulsar Wind Nebula: a two zone model