On energy velocity of pyroelectric medium

The fundamentals of energy process and energy velocity in the pyroelectric medium with generalized heat conduction theory are addressed firstly. From energy balance equation of pyroelectric medium, it is found that the energy density consists of the electric energy, the heat energy, the mechanical potential energy and the kinetic energy. The dissipation energy is attributed by the heat conduction, relaxation time and pyroelectric effect. The energy flux is also obtained explicitly and accordingly the energy velocity is defined. Plots of energy velocity and phase velocity in propagation and attenuation angle domain are presented, which show that the attenuation angle almost doesn´t influence phase velocity of quasilongitudinal, quasitransverse I, II wave modes, while plays great role on the temperature wave. The energy velocities of the four wave modes all decay with the attenuation angle.