Particle acceleration and magnetic field amplification by relativistic shocks in inhomogeneous media

Abstract

Particle acceleration and magnetic field amplification in relativistic shocks propagating in inhomogeneous media are investigated by three-dimensional magnetohydrodynamical (MHD) simulations and test-particle simulations. The MHD simulations show that the interaction between the relativistic shock and dense clumps amplifies the downstream magnetic field to the value expected from observations of the gamma-ray burst. The test-particle simulations in the electromagnetic field given by the MHD simulation show that particles are accelerated by the downstream turbulence and the relativistic shock. We provide the injection energy to the shock acceleration in this system. If the amplitude of upstream density fluctuations is sufficiently large, low-energy particles are initially accelerated to the injection energy by the downstream turbulence and then rapidly accelerated to higher energies by the relativistic shock. Therefore, the density fluctuation significantly affects particle acceleration in the relativistic shock.

8 pages, 5 figures, accepted for publication in ApJL

References in corpus (15)

• Particle acceleration in relativistic collisionless shocks: Fermi process at last?
• Equation of State in Relativistic Magnetohydrodynamics: variable versus constant adiabatic index
• On the efficiency of Fermi acceleration at relativistic shocks
• Production of magnetic energy by macroscopic turbulence in GRB afterglows
• Cosmic-Ray Acceleration at Ultrarelativistic Shock Waves: Effects of Downstream Short-Wave Turbulence
• First 3D Radiation-Hydrodynamic Simulations of Wolf-Rayet Winds
• Numerical Simulations of Supernova Remnant Evolution in a Cloudy Interstellar Medium
• Turbulent Magnetic Field Amplification by the Interaction of Shock Wave and Inhomogeneous Medium
• Reacceleration of electrons in supernova remnants
• Prospects for ultra-high-energy particle acceleration at relativistic shocks
• Relativistic Collisionless Shocks in Inhomogeneous Magnetized Plasmas
• Particle acceleration at ultrarelativistic, perpendicular shock fronts
• Fast Particle Acceleration at Perpendicular Shocks with Uniform Upstream Magnetic Field and Strong Downstream Turbulence
• Interaction of a Relativistic Magnetized Collisionless Shock with a Dense Clump
• Particle acceleration in a shock wave propagating to an inhomogeneous medium

Cited by in corpus (4)

• Collisionless shock in a relativistically hot unmagnetized electron-positron plasma
• Property of downstream turbulence driven by the special relativistic shock-clump interaction
• Very-high-energy gamma rays from cosmic rays escaping from Galactic black hole binaries
• Collisionless shocks having relativistic velocities in relativistically hot plasmas