Improved Cauchy horizon stability conjecture

An improved stability conjecture for Cauchy horizons is presented. The conjecture predicts the stability of Cauchy horizons based upon the behavior of test fields, and in the case of instability it also predicts the nature of the singularities produced. The results for Cauchy horizons in Reissner-Nordstr\"om, Kerr, Reissner-Nordstr\"om-de Sitter, Kerr-de Sitter, anti-de Sitter, and a type V LRS spacetime are reviewed. A new prediction is made for scalar fields in anti-de Sitter spacetime. The improved conjecture agrees with the stability and singularity types in all cases for which exact back reaction solutions have been found.