Inner-horizon instability and mass inflation in black holes

Gravitational collapse with rotation leaves a slowly decaying radiative tail which becomes infinitely blueshifted at the inner horizon of the resulting black hole. We study the gravitational effects of this on the inner structure of the hole, using a simple spherical model. In the presence of outflow from the collapsing star, the gravitational-mass parameter and the curvature are inflated at and within the inner horizon to values which, classically, are unlimited. Implications of this result are briefly discussed.