Absorption waves maintained by CO laser radiation

An experimental investigation was made of the action of pulsed CO laser radiation on metals in a power density range, averaged over the focal spot, of from 0.5 to 2.5 MW/cm². It was found that on restricting the radial expansion of the plasma jet a transition occurred from an evaporation interaction regime to an absorption wave in air. The experimentally determined parameters of the absorption wave were compared with those calculated on the basis of one-dimensional theories of a subsonic radiation wave and of optical detonation. Data are obtained on the thresholds for the formation of plasma near metal surfaces.