Thermal blooming of a partially coherent light beam

A theoretical investigation is presented of the thermal self-focusing and self-defocusing of a quasi-CW multimode spatially incoherent light beam propagating in an optically transparent stationary medium. The investigation is based on a numerical solution of the closed-form equation for the second-order spatial correlation function. Results are presented on the distribution of mean intensity in cross sections of focused and defocused beams, the transformation of the correlation radius, and the appearance of nonlinear 'noise' aberrations, leading to the breakdown of the statistical homogeneity of the beam.