Unified Bertotti-Robinson and Melvin Spacetimes

Abstract

We present a solution for the Einstein-Maxwell (EM) equations which unifies both the magnetic Bertotti-Robinson (BR) and Melvin (ML) solutions as a single metric in the axially symmetric coordinates t,ρ,z,φ. Depending on the strength of magnetic field the spacetime manifold, unlike the cases of separate BR and ML spacetime, develops singularity on the symmetry axis (ρ=0). Our analysis shows, beside other things that there are regions inaccessible to all null geodesics.