WhiskyMHD: a new numerical code for general relativistic magnetohydrodynamics

TL;DR

WhiskyMHD is a newly developed numerical code capable of simulating general relativistic magnetohydrodynamics in dynamic spacetimes, enabling advanced modeling of astrophysical phenomena involving compact objects and magnetic fields.

Contribution

The paper introduces WhiskyMHD, a novel high-resolution shock-capturing numerical code for solving the full set of GRMHD equations with adaptive mesh refinement in arbitrary spacetimes.

Findings

Successfully validated with relativistic Riemann problems

Accurately models stationary accretion onto black holes

Simulates oscillating magnetized stars in equilibrium

Abstract

The accurate modelling of astrophysical scenarios involving compact objects and magnetic fields, such as the collapse of rotating magnetized stars to black holes or the phenomenology of gamma-ray bursts, requires the solution of the Einstein equations together with those of general-relativistic magnetohydrodynamics. We present a new numerical code developed to solve the full set of general-relativistic magnetohydrodynamics equations in a dynamical and arbitrary spacetime with high-resolution shock-capturing techniques on domains with adaptive mesh refinements. After a discussion of the equations solved and of the techniques employed, we present a series of testbeds carried out to validate the code and assess its accuracy. Such tests range from the solution of relativistic Riemann problems in flat spacetime, over to the stationary accretion onto a Schwarzschild black hole and up to the evolution of oscillating magnetized stars in equilibrium and constructed as consistent solutions of the coupled Einstein-Maxwell equations.