2015/12/31 by E. V. Derishev, Evgeny V. Derishev, Tsvi Piran
Physics and Astronomy · #Acceleration #Active galactic nucleus #Astrophysics #Astrophysics and Cosmic Phenomena #Charged particle #Classical mechanics #Computational physics #Electron #Gamma-ray bursts and supernovae #Magnetic field #Magnetization #Nuclear physics #Particle (ecology) #Particle acceleration #Particle radiation #Physics #Pulsars and Gravitational Waves Research #Quantum electrodynamics #Quantum mechanics #Radiation #Relativistic beaming #Relativistic particle #Relativistic speed #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stw1175
MNRAS accepted, largely reworked presentation
openalex publication_date 2016/05/17 · arxiv created 2016/06/03 · arxiv updated 2016/06/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The mechanisms of particle acceleration and radiation, as well as magnetic field build-up and decay in relativistic collisionless shocks, are open questions with important implications to various phenomena in high-energy astrophysics. While the Weibel instability is possibly responsible for magnetic field build-up and diffusive shock acceleration is a model for acceleration, both have problems and current particle-in-cell simulations show that particles are accelerated only under special conditions and the magnetic field decays on a very short length-scale. We present here a novel model for the structure and the emission of highly relativistic collisionless shocks. The model takes into account (and is based on) non-local energy and momentum transport across the shock front via emission and absorption of high-energy photons. This leads to a pre-acceleration of the fluid and pre-amplification of the magnetic fields in the upstream region. Both have drastic implications on the shock structure. The model explains the persistence of the shock-generated magnetic field at large distances from the shock front. The dissipation of this magnetic field results in a continuous particle acceleration within the downstream region. A unique feature of the model is the existence of an ‘attractor’, towards which any shock will evolve. The model is applicable to any relativistic shock, but its distinctive features show up only for sufficiently large compactness. We demonstrate that prompt and afterglow gamma-ray bursts’ shocks satisfy the relevant conditions, and we compare their observations with the predictions of the model.