Non-linear model of particle acceleration at colliding shock flows

TL;DR

This paper introduces a non-linear, time-dependent model for particle acceleration near two approaching MHD shocks, relevant in stellar clusters, showing that such collisions produce harder high-energy particle spectra than isolated supernova remnants.

Contribution

The paper develops a novel non-linear model for particle acceleration at colliding MHD shocks, applicable to stellar clusters and supernova environments.

Findings

Accelerated particle spectra can be harder at colliding shocks.

Model applicable to various astrophysical systems with colliding MHD flows.

Potential explanation for nonthermal emissions in star-forming regions.

Abstract

Powerful stellar winds and supernova explosions with intense energy release in the form of strong shock waves can convert a sizeable part of the kinetic energy release into energetic particles. The starforming regions are argued as a favorable site of energetic particle acceleration and could be efficient sources of nonthermal emission. We present here a non-linear time-dependent model of particle acceleration in the vicinity of two closely approaching fast magnetohydrodynamic (MHD) shocks. Such MHD flows are expected to occur in rich young stellar cluster where a supernova is exploding in the vicinity of a strong stellar wind of a nearby massive star. We find that the spectrum of the high energy particles accelerated at the stage of two closely approaching shocks can be harder than that formed at a forward shock of an isolated supernova remnant. The presented method can be applied to model particle acceleration in a variety of systems with colliding MHD flows.