Nonlinear relaxation waves in ordered media
Abstract
The symmetric and nonsymmetric solutions for three-dimensional nonlinear waves in ordered media, following from the Landau–Khalatnikov equations for the relaxation of the order parameter, are found. It is shown that two of the three types of nonlinear waves are structurally stable, and the third type is unstable. The constants in the Landau–Khalatnikov equations are evaluated from the solutions of the kinetic equations for the distribution functions of the magnons and phonons with strong magnon–phonon interaction in the isothermal and nonisothermal cases. The effect of temperature fields in crystals accompanying the nonlinear waves on the dynamics of the nonlinear waves is studied. Criteria for the dynamical instabiity of the nonlinear waves are found.