New Constraints in General-Relativistic Magnetohydrodynamics Impacting Astrophysical Simulations

Recent research by Ian Cordeiro and colleagues has introduced significant findings in the field of general-relativistic magnetohydrodynamics (GRMHD). Their paper, titled "Causality Bounds on Dissipative General-Relativistic Magnetohydrodynamics," outlines necessary and sufficient conditions for a broad class of relativistic models that incorporate shear, bulk, and heat diffusion effects. The authors emphasize that causality imposes stringent limitations on the magnitude of nonideal effects and the emergence of kinetic instabilities within these models.

The study highlights the importance of these findings for fluid dynamical simulations of plasmas, particularly in environments near supermassive black holes. The constraints identified by the authors are crucial for ensuring that simulations accurately reflect the physical realities of such extreme astrophysical conditions.

The paper has been accepted for publication in Physical Review Letters and spans 16 pages, including one figure and supplemental material. The authors of this research include Ian Cordeiro, Enrico Speranza, Kevin Ingles, Fábio S. Bemfica, and Jorge Noronha. For further reading, the paper can be cited as follows: arXiv:2312.09970.