Thermodynamics of Shear Equilibration During Magnetic Reconnection Onset in Mixed-Equilibrium Current Sheets

TL;DR

This paper investigates how magnetic shear influences the onset of magnetic reconnection and current sheet equilibration using 2D PIC simulations, focusing on thermodynamic interactions and energy transfer processes.

Contribution

It provides new insights into the thermodynamic and electromagnetic dynamics during reconnection onset in high guide field regions, highlighting stages of pressure evolution and energy transfer mechanisms.

Findings

Identification of critical stages in current sheet equilibration.

Characterization of pressure evolution driven by density or temperature.

Analysis of electromagnetic energy transfer during reconnection onset.

Abstract

Magnetic shear across the polarity inversion line (PIL) plays an important role in the explosive nature of reconnection onset and in the equilibration of current sheets, acting as a source of free energy that can enhance or inhibit the onset process under certain conditions. In this study, we use a 2D PIC simulation to examine the local interaction between the reconnection guide field and thermodynamic variables during reconnection onset in a region of initially depleted thermal energy and enhanced magnetic energy in a large guide field background. We identify critical stages of the equilibration process, characterize intervals based on whether the pressure evolution is driven by changes in density or temperature, and discuss what these intervals imply about the evolution of local heat and work density. Finally, we examine power densities associated with electromagnetic field time evolution and electromagnetic energy transfer and compare to those related to thermodynamic changes.