Wave instability of a molten metal layer formed by intense laser irradiation

Wave structure of a molten metal layer flowing over the walls of a vapor-gas cavern that appears as an intense laser radiation penetrates deep into condensed media is studied theoretically taking into account surface tension, gravitation, thermocapillary effect, and nonuniform evaporation from the free surface of the melt. A long-wavelength evolution equation describing the evolution of nonlinear waves on the free surface of a plane molten layer is derived. The spatially periodic running solution to this equation is obtained, and the main characteristics (amplitude and period) of the nonlinear wave structures are determined.