Stability of the front of laser evaporation of metals under conditions of limited vapour expansion

The solutions of the dispersion equation for the perturbations of the front of laser evaporation of metals are studied for different Mach numbers M in the vaporised material flow. It is shown that the simultaneous manifestation of the hydrodynamic perturbations in the condensed medium and the gas-dynamic perturbations in the vapour flow for M < 1 significantly changes the dispersion curves compared to the cases of evaporation instability (M = 1) and Darrieus – Landau (M ≪ 1) instability.