Non-linear collisionless damping of Weibel turbulence in relativistic blast waves

Abstract

The Weibel/filamentation instability is known to play a key role in the physics of weakly magnetized collisionless shock waves. From the point of view of high energy astrophysics, this instability also plays a crucial role because its development in the shock precursor populates the downstream with a small-scale magneto-static turbulence which shapes the acceleration and radiative processes of suprathermal particles. The present work discusses the physics of the dissipation of this Weibel-generated turbulence downstream of relativistic collisionless shock waves. It calculates explicitly the first-order non-linear terms associated to the diffusive nature of the particle trajectories. These corrections are found to systematically increase the damping rate, assuming that the scattering length remains larger than the coherence length of the magnetic fluctuations. The relevance of such corrections is discussed in a broader astrophysical perspective, in particular regarding the physics of the external relativistic shock wave of a gamma-ray burst.

21 pages, 2 figures; to appear in Journal of Plasma Physics

References in corpus (10)

• Particle acceleration in relativistic collisionless shocks: Fermi process at last?
• On the structure of relativistic collisionless shocks in electron-ion plasmas
• Long Term Evolution of Magnetic Turbulence in Relativistic Collisionless Shocks: Electron-Positron Plasmas
• Magnetic field evolution in relativistic unmagnetized collisionless shocks
• On the efficiency of Fermi acceleration at relativistic shocks
• On Fermi acceleration and MHD-instabilities at ultra-relativistic magnetized shock waves
• Production of magnetic energy by macroscopic turbulence in GRB afterglows
• Cosmic-Ray Acceleration at Ultrarelativistic Shock Waves: Effects of Downstream Short-Wave Turbulence
• Particle Transport in intense small scale magnetic turbulence with a mean field
• Convective Instability of a Relativistic Ejecta Decelerated by a Surrounding Medium: An Origin of Magnetic Fields in GRBs?

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• Long-term Evolution of Relativistic Unmagnetized Collisionless Shocks
• A Narrow Uniform Core with a Wide Structured Wing: Modeling the TeV and Multi-wavelength Afterglows of GRB 221009A
• Constraints on Electron Acceleration in Gamma-Ray Bursts Afterglows from Radio Peaks
• Microphysics of Relativistic Collisionless Electron-ion-positron Shocks
• Magnetic field amplification by a plasma cavitation instability in relativistic shock precursors
• Particle acceleration at ultrarelativistic, perpendicular shock fronts
• Saturation of the asymmetric current filamentation instability under conditions relevant to relativistic shock precursors
• Jitter Mechanism as a Kind of Coherent Radiation: Constrained by the GRB 221009A Emission at 18 TeV
• Macroscopic magnetization of primordial plasma by virial shocks