Inner structure of a charged black hole: An exact mass-inflation solution

Recently, Poisson and Israel have shown how, when an electrically charged black hole is perturbed, its inner horizon becomes a singularity of infinite spacetime curvature---the mass-inflation singularity. In this paper we construct an exact mass-inflation solution of the Einstein-Maxwell equations, and use it to analyze the mass-inflation singularity. We find that this singularity is weak enough that its tidal gravitational forces do not necessarily destroy physical objects which attempt to cross it. The possible continuation of the spacetime through this weak singularity is discussed.