The general relativistic MHD dynamo equation

Abstract

The magnetohydrodynamic dynamo equation is derived within general relativity, using the covariant 1+3 approach, for a plasma with finite electric conductivity. This formalism allows for a clear division and interpretation of plasma and gravitational effects, and we have not restricted to a particular spacetime geometry. The results should be of interest in astrophysics and cosmology, and the formulation is well suited to gauge invariant perturbation theory. Moreover, the dynamo equation is presented in some specific limits. In particular, we consider the interaction of gravitational waves with magnetic fields, and present results for the evolution of the linearly growing electromagnetic induction field, as well as the diffusive damping of these fields.