On the angular dependence of the threshold of convective instability and the gaining coefficient for counter interacting waves

The angular dependence of the threshold of convective instability and the gaining coefficient for counter interacting waves have been studied. In the problem of stimulated scattering of a two-dimensionally localized pump wave, the dependence of the instability threshold and the amplification factor of counter propagating waves on the scattering angle has been found. It has been shown that with an increase of the scattering angle, the threshold and the gain increase.