Fluid and kinetic modelling for non-local heat transport in magnetic fusion devices

TL;DR

This paper develops a non-local heat transport model for magnetic fusion devices, combining fluid and kinetic approaches to better capture edge plasma behavior across different collisional regimes.

Contribution

It introduces a generalized Fourier law with a non-local kernel and integrates a kinetic simulation using the MPC algorithm for improved modeling.

Findings

Non-local heat flux model improves accuracy in low collisional regimes

Kinetic simulations validate fluid model predictions at different collisionalities

Bohm boundary condition is recovered with a volumetric loss term

Abstract

In order to improve the presently used ad hoc flux limiter treatment of parallel heat flux transport in edge plasma fluid codes we consider here a generalized version of the Fourier law implementing a non-local kernel for the heat flux computation. The Bohm boundary condition at the wall is recovered introducing a volumetric loss term representing the contribution of suprathermal particles to the energy out flux. As expected, this contribution is negligible in the strongly collisional regime while it becomes more and more dominant for marginally and low collisional regimes. In the second part of the paper, we consider a kinetic approach where collisions are considered using the Multi-Particle-Collision (MPC) algorithm. Kinetic simulation results at medium and low collisionality are also reported.