Steam and plasma bubble evolution on laser treating of a sample being in liquid

Abstract

An object of investigation is pointed - the metal articles being in water and exposed to pulse laser treating. The purpose of research was the investigation of the processes occurring near the metal target treated by pulse laser radiation with flux density ∼106 W/cm–2. The results of the experimental investigation of the pulse laser treating of a led target being in water are described. The process of steam and gas plume generation on the surface of the irradiated metal was investigated experimentally. The features of steam and gas plume form and dimensions evolution on different stages of the process (even after completion of laser treating of the material) were investigated. It is shown that when using GOR-100M operating in free oscillating regime (pulse duration 1.2 ms, laser radiation flux density ∼106 W/cm–2), the form of a crater developed on the irradiated target surface being in water essentially differs from the topography of the crater developed on the analogical target surrounded by air at normal pressure (105 Pa). It is pointed in the conclusions that the substantial difference of the forms of crater surfaces developed as a result of processing of the identical targets being in water or air by laser pulses with the identical parameters , determines by principally different character of plasma and steam and gas mixture flow in the mentioned cases.