Thermal self-interaction of light beams

A theoretical study is reported of the self-interaction of light beams during their propagation in weakly absorbing media. An analytic solution is obtained for thermal self-focusing of a light beam with a parabolic intensity distribution. The Ehrenfest theorem is used to obtain an expression for the shift of a light beam in a moving medium in the case of an arbitrary dependence of the velocity of this medium on the coordinate along the beam.