Thermal interaction of high-power laser radiation with gases

A theoretical analysis is presented of the thermal interaction of laser radiation with a medium at rest and with a medium in co- and counter-current flow over the path traversed by radiation. The operation of a gas lens for focusing high-power laser radiation is investigated for the case when radiation-induced heat generation makes an additional contribution to the temperature nonuniformity. Conditions required for the self-focusing of stationary Gaussian and circular beams, the intensity of which decreases toward the beam center, are examined. The dynamics of thermal and optical processes in the case of 'banana' self-focusing is considered.