Polarization of plane wave propagating inside elastic hexagonal system solids

Based on the reported physical parameters for hexagonal system solids, we have calculated the effects of anisotropy on polarization of plane P-wave propagation. Herein we report the results of calculations and the newly observed physical phenomena. It is found that, for a given propagation, if the polarization is parallel to the wave vector, so also to the Poynting vector. In such a case, the phase velocity is identical to the energy velocity; the quasi P-wave degenerates to a pure P-wave along the propagation. It is also noted that if the polarization is parallel to the Poynting vector but not to the wave vector, the propagating wave cannot be a pure P-wave. Furthermore, the polarization in a quasi P-wave may deviate from the wave vector for more than 45°, but the deviation from the Poynting vector is always less than 45°. The energy velocity of a quasi SV-wave can be larger than that of the quasi P-wave in some propagation directions, even though the phase velocity of a quasi SV-wave may never be larger than either the phase velocity or energy velocity of the quasi P-wave. Finally, in case of parameters ?=0 and δ*≠0, the polarization of a quasi P-wave has an observed symmetry at a 45° phase angle. The anisotropy of a hexagonal system solid determines if a pure P-wave can be created and what the propagation direction is for a plane wave propagating inside such a hexagonal system solid.