Neutron-loaded outflows in gamma-ray bursts |
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| Authors: | Elena M Rossi rei M Beloborodov Martin J Rees |
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| Institution: | Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 51, Cambridge, MA 02138, USA |
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| Abstract: | The force-free limit of magnetohydrodynamics (MHD) is often a reasonable approximation to model black hole and neutron star magnetospheres. We describe a general relativistic force-free (GRFFE) formulation that allows general relativistic magnetohydrodynamic (GRMHD) codes to directly evolve the GRFFE equations of motion. Established, accurate and well-tested conservative GRMHD codes can simply add a new inversion piece of code to their existing code, while continuing to use all the already-developed facilities present in their GRMHD code. We show how to enforce the E · B = 0 constraint and energy conservation, and we introduce a simplified general model of the dissipation of the electric field to enforce the B 2? E 2 > 0 constraint. We also introduce a simplified yet general method to resolve current sheets, without much reconnection, over many dynamical times. This formulation is incorporated into an existing GRMHD code ( harm ), which is demonstrated to give accurate and robust GRFFE results for Minkowski and black hole space–times. |
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| Keywords: | black hole physics magnetic fields MHD methods: numerical galaxies: jets gamma-rays: bursts |
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