Time-resolved characterization of the formation of a collisionless shock

TL;DR

This study provides a detailed time-resolved analysis of how unmagnetized collisionless shocks form in a laboratory setting, revealing the transition from double layers to shock structures stabilized by ion reflection, analogous to astrophysical shocks.

Contribution

It presents the first temporally and spatially resolved detection of shock formation stages in a laser-driven experiment, supported by simulations and theory.

Findings

Transition from double layer to symmetric shock observed

Ion reflection stabilizes the shock front

Laboratory shock formation mimics astrophysical processes

Abstract

We report on the temporally and spatially resolved detection of the precursory stages that lead to the formation of an unmagnetized, supercritical collision-less shock in a laser-driven laboratory experiment. The measured evolution of the electrostatic potential associated with the shock unveils the transition from a current free double layer into a symmetric shock structure, stabilized by ion reflection at the shock front. Supported by a matching Particle-In-Cell simulation and theoretical considerations, we suggest that this process is analogeous to ion reflection at supercritical collisionless shocks in supernova remnants.