Pressure-Strain Interaction: III. Particle-in-Cell Simulations of Magnetic Reconnection

TL;DR

This paper uses particle-in-cell simulations to analyze the pressure-strain interaction during magnetic reconnection, offering new decompositions and coordinate analyses to understand energy conversion in plasma processes.

Contribution

It introduces an alternative decomposition of pressure-strain interaction focusing on flow effects and applies it to magnetic reconnection simulations in both Cartesian and magnetic field-aligned coordinates.

Findings

Identified mechanisms of positive and negative pressure-strain during reconnection

Demonstrated the utility of magnetic field-aligned coordinates for analysis

Provided a framework for interpreting pressure-strain in observational data

Abstract

How energy is converted into thermal energy in weakly collisional and collisionless plasma processes such as magnetic reconnection and plasma turbulence has recently been the subject of intense scrutiny. The pressure-strain interaction has emerged as an important piece, as it describes the rate of conversion between bulk flow and thermal energy density. In two companion studies, we presented an alternate decomposition of the pressure-strain interaction to isolate the effects of converging/diverging flow and flow shear instead of compressible and incompressible flow, and we derived the pressure-strain interaction in magnetic field-aligned coordinates. Here, we use these results to study pressure-strain interaction during two-dimensional anti-parallel magnetic reconnection. We perform particle-in-cell simulations and plot the decompositions in both Cartesian and magnetic field-aligned coordinates. We identify the mechanisms contributing to positive and negative pressure-strain interaction during reconnection. This study provides a roadmap for interpreting numerical and observational data of the pressure-strain interaction, which should be important for studies of reconnection, turbulence, and collisionless shocks.