Impedance method for calculation of thermoelastic interaction of surface acoustic waves in solids

A thermal impedance has been introduced for the solution of the problem of the thermoelastic interaction of surface acoustic waves (SAW) in solids. The analytic thermal impedance is obtained for isotropic solids from the weak thermoelastic coupling approximation. The value of thermal impedance obtained depends only on three parameters: the isothermal SAW velocity, the velocity for the case without dissipation of heat from the solid surface, and a thermal impedance without acoustic waves. The extended approach allows us to investigate and analyze the effect of different surface layers and continuous materials on the thermoelastic attenuation and velocity dispersion of the SAW. For example, an ideal heat conductive layer reduces the thermoelastic SAW attenuation to zero. By analogy with excitation of the SAW by means of a high frequency periodic electric field the problem of the excitation of the SAW by means of a thermal high frequency periodic perturbation (for example by means of a laser) may easily be solved with the help of the surface thermal impedance