TRANSIENT SELF-INTERACTION OF A VERTICAL LASER-BEAM

The thermal self-interaction regimes are identified and analysed for a vertical laser beam under conditions of free convection in an absorbi ng medium, The characteristic times, velocities, scales of temperature changes, and scaling parameters are determined for all the regimes. T he equations of conservation of the medium are obtained ana solved num erically in the approximation of paraxial wave optics under strong. an d moderate convection conditions. A comparison is made with the publis hed experimental results. The reason for the appearance of turbulence at low Reynolds numbers is considered on the basis of these experiment al results.