ELECTROMAGNETIC AND ELASTODYNAMIC POINT-SOURCE EXCITATION OF UNBOUNDED HOMOGENEOUS ANISOTROPIC MEDIA

Plane electromagnetic as well as plane elastodynamic waves in anisotro pic media exhibit a different direction of their phase and energy prop agation, resulting in slowness and group velocity surfaces. Of course, the availability of plane wave solutions gives rise to a spectral pla ne wave decomposition of point source excitations, i.e., Green's funct ions. Unfortunately, the coordinate-free closed-form solution of dyadi c (electric) Green's functions in the R omega space is only known for electromagnetic (generalized) uniaxial media. Utilizing the relation b etween phase and group velocities of plane waves in uniaxial media we have been able to show that the phase and amplitude of the Green's fun ction is related to the group velocity; i.e., time domain wave fronts reproduce group velocity surfaces. This has also been verified through numerical results obtained by the three-dimensional (3-D) electromagn etic finite integration technique code. In elastodynamics, where simil ar analytical results for anisotropic media are not available, we conf irm this behavior with our numerical 3-D elastodynamic finite integrat ion technique code. For electromagnetic uniaxial media, we present an analytic method to derive the dyadic far-field Green's function in R o mega space from K omega space directly by utilizing the duality princi ple between wave vectors and ray vectors without performing the 3-D in verse Fourier transform from K omega space to R omega space analytical ly.