Cavitation instability in unmagnetized relativistic pair shocks

TL;DR

This paper studies how plasma cavities form in unmagnetized relativistic pair shocks, linking microscopic Weibel turbulence to large-scale magnetic fields through a cavitation instability.

Contribution

It introduces a minimal fluid model explaining cavitation instability caused by asymmetric Weibel instability in relativistic shocks.

Findings

Cavities naturally form as a nonlinear outcome of Weibel instability

The fluid model captures key features of the cavitation process

Potential link between kinetic turbulence and macroscopic magnetic fields

Abstract

We investigate the formation of plasma cavities in unmagnetized relativistic pair shocks and demonstrate that these cavities emerge naturally as a nonlinear consequence of asymmetric Weibel instability. We provide an intuitive physical picture and a minimal fluid model that captures the essential features of this cavitation instability and compare them with PIC results. This mechanism may provide the missing link between kinetic Weibel turbulence and macroscopic magnetic fields in astrophysical shocks.