Physics of relativistic shocks

TL;DR

This paper reviews the micro-physics of relativistic collisionless shocks in astrophysics, emphasizing the role of plasma instabilities like the Weibel instability and introducing a model of upstream pre-conditioning by cosmic-ray-driven instabilities.

Contribution

It presents a recent model of upstream pre-conditioning in unmagnetized regions via cosmic-ray-driven Weibel-type instabilities, advancing understanding of shock micro-physics.

Findings

Strong magnetic fields generated efficiently by plasma instabilities.

Pre-conditioning of upstream regions influences shock formation.

Enhanced understanding of shock micro-physics in astrophysical contexts.

Abstract

Relativistic shocks are usually thought to occur in violent astrophysical explosions. These collisionless shocks are mediated by a plasma kinetic streaming instability, often loosely referred to as the Weibel instability, which generates strong magnetic fields "from scratch" very efficiently. In this review paper we discuss the shock micro-physics and present a recent model of "pre-conditioning" of an initially unmagnetized upstream region via the cosmic-ray-driven Weibel-type instability.