Generation of harmonics and degenerate parametric interaction of longitudinal acoustic waves in solids with quadratically-bimodular nonlinearity

The theoretical study by the perturbation method of the acoustic effects at the degenerate parametric interaction of a strong high-frequency and a weak low-frequency longitudinal elastic waves in microinhomogeneous solids with a quadratically-bimodular nonlinearity is presented. The amplitude dependences for the following nonlinear effects are revealed and analyzed: generation of second and fourth harmonics of the strong high-frequency wave and changes in the amplitude (amplification or weakening) of the weak low-frequency wave under the action of the strong high-frequency wave. It is noted that the experimental study of these effects can be used to determine nonlinear parameters of such solids.