Abstract. We consider the evolution of electromagnetic fields in curved spacetimes and calculate the exact wave equations for the associated electric and magnetic components. Our analysis is fully covariant, applies to a general spacetime and isolates all the sources that affect the propagation of these waves. Among others, we explicitly show how the different components of the gravitational field act as driving sources of electromagnetic disturbances. When applied to perturbed Friedmann–Robertson–Walker cosmologies, our results argue for a superadiabatic-type amplification of large-scale cosmological magnetic fields in Friedmann models with open spatial curvature.

PACS numbers: 04.20.−q, 98.80.−k, 41.20.Jb

Print publication: Issue 2 (21 January 2005)
Received 22 July 2004, in final form 2 November 2004
Published 29 December 2004