Momentum transport and nonlocality in heat-flux-driven magnetic reconnection in high energy density plasmas

TL;DR

This paper investigates heat-flux-driven magnetic reconnection in high-energy-density plasmas, revealing that nonlocal heat-flux-viscosity plays a key role in electron dissipation and reconnection dynamics.

Contribution

It introduces a kinetic simulation and a first-principles derived generalized Ohm's law to explain the dissipation mechanism involving nonlocal heat-flux-viscosity in this regime.

Findings

Nonlocal heat-flux-viscosity provides dissipation in reconnection.

Reconnection involves a compression stage and a steady stage.

Current sheet width is several electron mean-free-paths.

Abstract

Recent theory has demonstrated a novel physics regime for magnetic reconnection in high-energy-density plasmas where the magnetic field is advected by heat flux via the Nernst effect. Here we elucidate the physics of the electron dissipation layer in this regime. Through fully kinetic simulation and a generalized Ohm's law derived from first principles, we show that momentum transport due to a nonlocal effect, the heat-flux-viscosity, provides the dissipation mechanism for magnetic reconnection. Scaling analysis and simulations show that the reconnection process is comprised of a magnetic field compression stage and quasi-steady reconnection stage, and the characteristic width of the current sheet in this regime is several electron mean-free-paths. These results show the important interplay between nonlocal transport effects and generation of anisotropic components to the distribution function.