Stochastic electron acceleration during spontaneous turbulent reconnection in a strong shock wave

Abstract

Shocking! Particle accelerators in space The acceleration of charged particles to high energies has been a major mystery, with a number of competing theories based on plasma physics. Many include the concept of turbulence, but with different roles. For example, shock-based theories emphasize the importance of turbulence developed from an unstable shock layer, whereas turbulent reconnection theories emphasize interactions of multiple reconnection sites. Matsumoto et al. present results of a large particle-in-cell simulation and examine how electrons are accelerated in the transition layer of a fast nonrelativistic shock (see the Perspective by Ji and Zweibel). Surprisingly, they find that when the shock is strong enough, charged particles (electrons in this case) are efficiently accelerated by turbulent reconnection within a turbulent shock layer containing multiscale structures. Science , this issue p. 974 ; see also p. 944