Particle heating and acceleration by reconnecting and non-reconnecting Current Sheets

TL;DR

This study investigates how reconnecting and non-reconnecting current sheets in turbulent plasmas contribute to particle heating and acceleration, revealing their combined effects on energy distribution and transport in solar phenomena.

Contribution

It introduces a Monte Carlo simulation analyzing the combined effects of fractal reconnecting and non-reconnecting current sheets on particle energization in turbulent plasmas.

Findings

Reconnecting current sheets accelerate particles and form power-law energy tails.

Non-reconnecting current sheets contribute to plasma heating, relevant to solar corona and flare heating.

The combined mechanisms influence particle energy distribution and transport properties.

Abstract

In this article, we study the physics of charged particle energization inside a strongly turbulent plasma, where current sheets naturally appear in evolving large-scale magnetic topologies, but they are split into two populations of fractally distributed reconnecting and non-reconnecting current sheets (CS). In particular, we implement a Monte Carlo simulation to analyze the effects of the fractality and we study how the synergy of energization at reconnecting CSs and at non-reconnecting CSs affects the heating, the power-law high energy tail, the escape time, and the acceleration time of electrons and ions. The reconnecting current sheets (RCS) systematically accelerate particles and play a key role in the formation of the power-law tail in energy distributions. On the other hand, the stochastic energization of particles through their interaction with non-reconnecting CSs can account for the heating of the solar corona and the impulsive heating during solar flares. The combination of the two acceleration mechanisms (stochastic and systematic), commonly present in many explosive events of various sizes, influences the steady-state energy distribution, as well as the transport properties of the particles in position- and energy-space. Our results also suggest that the heating and acceleration characteristics of ions and electrons are similar, the only difference being the time scales required to reach a steady state.