Gravitomagnetic Instabilities of Relativistic Magnetohydrodynamics
Abstract
We study gravitomagnetic instabilities of a static homogeneous medium with an aligned magnetic field in the two contexts of relativistic magnetohydrodynamics (MHD): first, MHD with postNewtonian (PN) corrections, and second, special relativistic (SR) MHD with weak gravity. The analysis in the PN MHD is made without taking the temporal gauge condition, thus results are gaugeinvariant. The PN corrections of the internal energy, pressure, sound velocity, and the Alfvén velocity lower the critical (Jeans) wavelength. All relativistic effects tend to destabilize the system. Although the SR MHD with weak gravity is presented in the harmonic gauge, in the presence of gravity the stability analysis is strictly valid to Newtonian order. In the absence of gravity, the SR MHD is independent of the gauge condition. We present the plane wave velocities and the stability criteria in both cases.
 Publication:

The Astrophysical Journal
 Pub Date:
 January 2021
 DOI:
 10.3847/15384357/abc422
 arXiv:
 arXiv:2010.01489
 Bibcode:
 2021ApJ...906...22N
 Keywords:

 Gravitation;
 Gravitational instability;
 Magnetohydrodynamics;
 Relativity;
 661;
 668;
 1964;
 1393;
 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 10 pages, 4 figures