Calculation the efficiency of energy transfer from nanosecond CO₂-laser pulses to the iron target during plasma appearance

The steel target evaporation and the gas-dynamic processes were calculated, thenfollowed by the plasma creation on in the metal vapor under the influence of nanosecond pulses were calculated. Mathematical model based on the Euler equations for the inviscid gas flow in conjunction statement with the radiation transfer equation in the diffusion multi-group approximation and the heat equation in solid metal was formulated. Nonlinear evaporation, depending on the energy entering to the target surface, was calculated using analytical expressions for the Knudsen layer. The structures of gas-dynamic flows with the formation of shock waves in an ambient gas (air) in the active vaporization mode and during plasma formation are were studied, also the thermal state of the target is was determined in the one-dimensional formulation. The comparison of the efficiency of energy transfer to the target is was made in both cases, : from laser radiation directly and when plasma appearsappeared, by means of thermal radiation. The significant increase in the adsorption coefficient of energy in the case of the appearance of plasma is shown. (paper)