Liquid-vapor phase transition and droplet formation by subpicosecond laser heating

The expansion of a thin metallic layer isochorically heated by a subpicosecond laser pulse is studied theoretically and numerically. An analytical model that accounts for the liquid-vapor phase transition in expanding flow is developed. Numerical simulations performed for an aluminum target that is described by a multiphase equation of state confirm the analytical model. A repartition of the liquid and vapor phases in the expanding cloud is studied and the expressions for sizes of liquid droplets formed in the relaxation process are obtained. These estimates are in agreement with recent experimental and numerical results.