Anisotropic thermal conduction on a moving mesh for cosmological simulations

Talbot, Rosie Y., Pakmor, Rüdiger, Pfrommer, Christoph, Springel, Volker, Werhahn, Maria, Bieri, Rebekka and van de Voort, Freeke ORCID: https://orcid.org/0000-0002-6301-638X 2025. Anisotropic thermal conduction on a moving mesh for cosmological simulations. Monthly Notices of the Royal Astronomical Society , staf1073. 10.1093/mnras/staf1073

PDF - Accepted Post-Print Version Available under License Creative Commons Attribution. Download (6MB)

Abstract

In weakly collisional, strongly magnetised plasmas such as the intracluster medium (ICM), hot accretion flows and the solar corona, the transport of heat and momentum occurs primarily along magnetic field lines. In this paper we present a new scheme for modelling anisotropic thermal conduction which we have implemented in the moving mesh code AREPO. Our implementation uses a semi-implicit time integration scheme which works accurately and efficiently with individual timestepping, making the scheme highly suitable for use in cosmological simulations. We apply the scheme to a number of test-problems including the diffusion of a hot patch of gas in a circular magnetic field, the progression of a point explosion in the presence of thermal conduction, and the evolution and saturation of buoyancy instabilities in anisotropically conducting plasmas. We use these idealised tests to demonstrate the accuracy and stability of the solver and highlight the ways in which anisotropic conduction can fundamentally change the behaviour of the system. Finally, we demonstrate the solver’s capability when applied to highly non-linear problems with deep timestep hierarchies by performing high-resolution cosmological zoom-in simulations of a galaxy cluster with conduction. We show that anisotropic thermal conduction can have a significant impact on the temperature distribution of the ICM and that whistler suppression may be relevant on cluster scales. The new scheme is, therefore, well suited for future work which will explore the role of anisotropic thermal conduction in a range of astrophysical contexts including the ICM of clusters and the circumgalactic medium of galaxies.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Physics and Astronomy
Publisher:	Oxford University Press
ISSN:	0035-8711
Date of First Compliant Deposit:	9 July 2025
Date of Acceptance:	23 June 2025
Last Modified:	09 Jul 2025 10:45
URI:	https://orca.cardiff.ac.uk/id/eprint/179652

Actions (repository staff only)

Edit Item