|Date||Oct 11, 2016|
We consider the linear scalar wave equation on a fixed subextremal Reissner-Nordström spacetime with non-vanishing charge. We show that generic smooth and compactly supported initial data on a Cauchy hypersurface give rise to solutions with infinite nondegenerate energy near the Cauchy horizon in the interior of the black hole. This instability is related to the celebrated blue shift effect in the interior of the black hole. The problem is motivated by the strong cosmic censorship conjecture and it is expected that for the full nonlinear Einstein-Maxwell system, this instability leads to a singular Cauchy horizon for generic small perturbations of Reissner-Nordström spacetime. This is a joint work with J. Luk (Stanford U.).