Role of ejecta clumping and back-reaction of accelerated cosmic rays in the evolution of supernova remnants

TL;DR

This paper investigates how ejecta clumping and cosmic ray back-reaction influence the evolution and instabilities of supernova remnants using detailed 3D MHD simulations.

Contribution

It presents a comprehensive 3D MHD model that includes ejecta clumping and cosmic ray back-reaction effects on supernova remnant evolution.

Findings

Ejecta clumping promotes strong RT instabilities at the contact discontinuity.

Cosmic ray back-reaction affects shock dynamics and remnant expansion.

Instabilities can extend upstream, influencing shock structure.

Abstract

The thermal structure of the post-shock region of a young supernova remnant (SNR) is heavily affected by two main physical effects, the back-reaction of accelerated cosmic rays (CRs) and the Rayleigh-Taylor (RT) instabilities developing at the contact discontinuity between the ejecta and the shocked interstellar medium (ISM). Here, we investigate the role played by both physical mechanisms in the evolution of SNRs through detailed 3D MHD modeling. Our model describes the expansion of the remnant through a magnetized ISM, including consistently the initial ejecta clumping and the effects on shock dynamics due to back-reaction of accelerated CRs. We discuss the role of the initial ejecta clumpiness in developing strong instabilities at the contact discontinuity which may extend upstream to the main shock and beyond.