Design of experiments characterising heat conduction in magnetised, weakly collisional plasma

TL;DR

This paper introduces a new experimental platform to study heat conduction in magnetised, weakly collisional plasma, aiming to better understand thermal transport affected by microinstabilities like the whistler heat-flux instability.

Contribution

The paper presents a novel experimental setup on the Orion laser to characterize whistler-regulated thermal conductivity in high-{eta} plasma, supported by simulation validation.

Findings

Simulations predict over an order of magnitude suppression of thermal conductivity.

The platform can effectively study microinstability effects on heat transport.

Design assessment shows the platform's potential for experimental investigation.

Abstract

Heat conduction in weakly collisional, magnetised plasma is challenging to model accurately due to multifaceted physics governing heat-carrying electrons, including microinstabilities that scatter electrons and modify heat transport. Capturing these effects requires multidimensional kinetic theory simulations, which are computationally expensive. Experimental constraints overcome this issue, resulting in improved understanding of thermal transport in systems such as the intra-cluster medium of galaxy clusters, and the hot-spot in inertial confinement fusion. In this paper, we present a new experimental platform that produces a weakly collisional high-\b{eta} plasma expected to be susceptible to the whistler heat-flux instability. This platform, to be fielded on the Orion laser, enables characterisation of whistler-regulated thermal conductivity. The platform design is assessed using radiation-magnetohydrodynamics simulations with the code FLASH. Simulations using three thermal conduction models predict conductivity suppression by over an order of magnitude relative to the Spitzer value at whistler saturation, demonstrating the efficacy of the platform.