Instability of a light beam and its decomposition with thermal self-stress in a moving medium

On the basis of linearized equations for perturbations in a one-dimensional light beam propagating in a moving medium with thermal nonlinearity, the article shows the possibility of an exponential growth of these perturbations with an intensity above the critical in the beam. Numerical solutions were carried out for the nonlinear equations of the propagation of Gaussian beams, showing that small perturbations can lead to decomposition of the beams.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 21, No. 11, pp. 1610–1617, November, 1978.