Gießen 2024 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 13: Numerical Relativity

GR 13.1: Talk

Wednesday, March 13, 2024, 17:30–17:50, HBR 14: HS 2

Divergence-Free Constraint Treatment in General-Relativistic Magneto-Hydrodynamic Simulations — •Anna Neuweiler — Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476, Potsdam, Germany

Magnetic fields have a significant impact on the post-merger dynamics of binary neutron star systems, as they influence the lifetime of the remnant as well as the outflow of matter. Their inclusion in numerical relativity is however not trivial since additional equations have to be solved and constraints have to be fulfilled, in particular the divergence-free constraint. We have recently enabled our numerical-relativity code BAM to perform general relativistic magneto-hydrodynamic simulations with hyperbolic divergence-cleaning, which introduces a new variable to damp the divergence. Although this method is simpler than other schemes used in the literature, one advantage is that higher-order reconstruction schemes can be used straightforward. To evaluate the impact, we compare our results for simple tests with other codes using different divergence-free constraint treatments. Finally, we perform binary neutron star simulations and analyze the differences.

Keywords: hydrodynamics; magnetic fields