Spectra of magnetic fluctuations and relativistic particles produced by a nonresonant wave instability in supernova remnant shocks

TL;DR

This paper models magnetic turbulence amplification by nonresonant instabilities in supernova remnant shocks, linking turbulence cascading to observable X-ray features and providing a nonlinear framework for particle acceleration.

Contribution

It introduces a self-consistent nonlinear model of magnetic field amplification and particle acceleration in supernova shocks, emphasizing the role of turbulence cascading.

Findings

Strong magnetic field amplification occurs with suppressed turbulence cascading.

Discrete peaks in turbulence spectrum influence synchrotron X-ray emissions.

The shock precursor structure varies significantly with turbulence cascading efficiency.

Abstract

We model strong forward shocks in young supernova remnants with efficient particle acceleration where a nonresonant instability driven by the cosmic ray current amplifies magnetic turbulence in the shock precursor. Particle injection, magnetic field amplification (MFA) and the nonlinear feedback of particles and fields on the bulk flow are derived consistently. The shock structure depends critically on the efficiency of turbulence cascading. If cascading is suppressed, MFA is strong, the shock precursor is stratified, and the turbulence spectrum contains several discrete peaks. These peaks, as well as the amount of MFA, should influence synchrotron X-rays, allowing observational tests of cascading and other assumptions intrinsic to the nonlinear model of nonresonant wave growth.