First order particle acceleration in magnetically-driven flows

TL;DR

This paper shows that particles can be systematically accelerated through curvature drift in magnetically-driven flows, which could explain non-thermal particle distributions in various astrophysical environments.

Contribution

It introduces a universal particle acceleration mechanism via curvature drift in magnetic tension-driven flows, applicable to many astrophysical contexts.

Findings

Particles gain energy in magnetic tension-driven flows.

Dynamo processes lead to particle cooling.

Mechanism likely explains non-thermal particles in astrophysics.

Abstract

We demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic (MHD) turbulence, where magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions. The opposite process, such as dynamo, will actually result in the net cooling of particles by the curvature drift. Being very generic, this acceleration mechanism is likely to be responsible in production of non-thermal particle distribution in magnetically-dominant environments such as solar chromosphere, pulsar magnetosphere, jets from supermassive black holes, $\gamma$-ray bursts, etc.