OPTICAL TURBULENCE AND (MINIMAL) THERMAL SELF-DEFOCUSING OF VERTICAL LASER-BEAM IN LIQUIDS AND GASES

Optical turbulence of a new type determined by a vertical laser beam filamentation at thermal self-defocusing in gases and liquids is considered. It is shown that light-induced convective flow along the laser beam yields optimal self-defocusing and optimal (nonlinear) radius of the coherent radiation. The minimal beam divergence is achieved, and a granular fluctuating radiative structure is formed. Optical turbulence is prior to the hydrodynamic turbulent convection, and is not connected with convective instabilities or convective structures in liquids. The obtained results are compared with the available experimental data.