Thermoelastic stresses as a mechanism of electromagnetic-acoustic transformation

The excitation of thermal waves of frequency 2$\omega$ in an anisotropic conductor by an electromagnetic wave of the same frequency incident on its surface is investigated. The normal to the metal surface does not coincide with the axis of symmetry of the conductor. Due to the thermoelectric effect, oscillations of temperature appear in the metal which, in turn, excite ultrasonic waves as a result of thermoelastic stresses. The role played by the constant, relatively high, but nonquantizing magnetic field in the linear thermoelastic generation of sound has been investigated. The nonlinear (at a frequency of 2$\omega$) thermoelastic generation of sound has been studied and an analysis is given of the experimental situation in this field.