Formation of a plasma in a vapor layer produced by the action of laser radiation on a solid

A numerical tolution is obtained of the one-dimensional planar transient problem of expansion into vacuum of a vapor formed by the action of a laser radiation on a solid. An arbitrary shape of a laser radiation pulse is considered. Allowance is made for the difference between the temperatures of electrons and ions (atoms) and for the transfer of heat from the evaporation wave to the solid by heat conduction. As in the equilibrium case, an absorption flash appears at sufficiently high radiation fluxes, i.e., a plasma layer is formed in which the degree of ionization is of the order of unity and which absorbs strongly the laser radiation. Calculations yield a description of the process within the framework of the assumptions made and, in particular, make it possible to predict the time and location of an absorption flash.