The mechanism of pore formation due to the capture of gas bubbles in the process of excitation of low-frequency capillary waves and alternating collapses in the penetration channel under laser action is studied experimentally. It is shown that bubble capture is provided by the main vibrational mode, the wavelength of which is related to the channel depth as λ=4L/3.

A qualitative analysis of changes in hydrodynamic parameters during keyhole formation by thermocapillary melt removal under the point action of CW laser radiation is presented. It is established that rapid surface deformation leads to adhesion of the viscous sublayer to the melting boundary and creation the shear structure of thermocapillary flow which stimulates acceleration of keyhole growth.