The crossed-beam energy transfer model without empirical factor for multi-beam irradiation of a spherical laser target

Stimulated Brillouin scattering of laser radiation in an expanding plasma during compression of a spherical target can significantly reduce the fraction of absorbed energy. A model of CBET (crossed-beam energy transfer) stimulated scattering under multi-beam irradiation of a spherical target has been developed. The model does not contain empirical factor, unlike the model known in the literature. This makes it possible to use it in calculations for the conditions of planned experiments. Calculations of the fraction Δ CB of energy released from the plasma due to CBET scattering for experimental conditions at the OMEGA installation have been carried out. It is shown that this fraction depends on the factor f e of the electron heat flux limitation. With f e values in the range 0.04–0.06, the calculated values of Δ CB (0.12–0.084) are close to the value 0.1 obtained in the experiment and in numerical simulation at f e = 0.06.