Stability of cosmological detonation fronts.

We present results of a linear stability analysis of relativistic detonation fronts, which have been considered as representing phase interfaces in cosmological first order phase transitions. After discussing general stability conditions for detonation fronts, we concentrate on the properties of the fronts with respect to corrugation instabilities and discuss separately the cases of Chapman-Jouguet and strong detonation waves. Contrarily to what recently claimed, we find that strong detonations are both evolutionary and stable with respect to corrugations of the front. Moreover, Chapman-Jouguet detonations appear to be unconditionally linearly stable. The implications of the stability results for first order cosmological phase transitions are presented and a discussion of the causal structure of reaction fronts is also given.