Dynamics of four-wave oscillation due to a thermal nonlinearity with amplification in a feedback loop

A model allowing for transient hydrodynamic processes is used in numerical experiments on generation of optical radiation by a four-wave interaction due to a thermal nonlinearity with amplification in a feedback loop. The results reveal characteristic features of the development of such generation and of the dynamics of perturbation of the density of the nonlinear medium due to the presence of the loop and also due to the influence of acoustic vibrations in the medium.