Pressure-Strain Interaction: II. Decomposition in Magnetic Field-Aligned Coordinates

TL;DR

This paper derives an analytical expression for pressure-strain interaction in magnetic field-aligned coordinates, revealing eight physical mechanisms relevant to plasma processes like reconnection and turbulence, and accessible to satellite measurements.

Contribution

It introduces a novel decomposition of pressure-strain interaction in magnetic field-aligned coordinates, clarifying physical mechanisms in magnetized plasmas.

Findings

Eight groups of terms representing different physical mechanisms.

Physical descriptions provided for each term.

Relevance to satellite measurements of plasma processes.

Abstract

In weakly collisional and collisionless magnetized plasmas, the pressure-strain interaction describes the rate of conversion between bulk flow and thermal energy density. In this study, we derive an analytical expression for the pressure-strain interaction in a coordinate system with an axis aligned with the local magnetic field. The result is eight groups of terms corresponding to different physical mechanisms that can contribute to the pressure-strain interaction. We provide a physical description of each term. The results are immediately of interest to weakly collisional and collisionless magnetized plasmas and the fundamental processes that happen therein, including magnetic reconnection, magnetized plasma turbulence, and collisionless shocks. The terms in the field-aligned coordinate decomposition are likely accessible to measurement with satellite observations.