Energy dissipation in astrophysical simulations: results of the Orszag-Tang test problem

Proceedings of RAGtime / Energy dissipation in astrophysical simulations: results of the Orszag-Tang test problem

Energy dissipation in astrophysical simulations: results of the Orszag-Tang test problem

Authors

Fatemeh Kayanikhoo, Miljenko Čemeljić, Maciek Wielgus and Włodek Kluźniak

Abstract

The magnetic field through the magnetic reconnection process affects the dynamics and structure of astrophysical systems. Numerical simulations are the tools to study the evolution of these systems. However, the resolution, dimensions, resistivity, and turbulence of the system are some important parameters to take into account in the simulations. In this paper, we investigate the evolution of magnetic energy in astrophysical simulations by performing a standard test problem for MHD codes, Orszag-Tang. We estimate the numerical dissipation in the simulations using state-of-the-art numerical simulation code in astrophysics, PLUTO. The estimated numerical resistivity in 2D simulations corresponds to the Lundquist number ≈ 104 in the resolution of 512 × 512 grid cells. It is also shown that the plasmoid unstable reconnection layer can be resolved with sufficient resolutions. Our analysis demonstrates that in non-relativistic magnetohydrodynamics simulations, magnetic and kinetic energies undergo conversion into internal energy, resulting in plasma heating.

Keywords

Magnetohydrodynamics – magnetic energy dissipation – resistivity – numerical simulations – PLUTO

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