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``Electromagnetic'' slowness surfaces

The electromagnetic slowness surfaces for PZT2 on the other hand, do not show any anomalous behavior. PZT2 is a strongly birefringent material. Thus we can clearly see the two wavetypes propagating at speeds comparable to that of electromagnetic waves. Both slowness surfaces touch at the vertical axis (symmetry axis). The inside surface has an electric displacement direction which is orthogonal to that on the outside surface (a manifestation of Maxwell's equations). The shape is ellipsoidal according to the structure of the electric permittivity and magnetic permeability tensors. Including the piezoelectric stress coefficients in the calculation results in only minor effects on those two wavetypes.

In quartz the propagation velocities of the two electromagnetic waves are very close; they are only distinguishable by looking at both the outside and the inside slowness surface. The inside surface has an electric displacement direction which is orthogonal to that on the outer surface (a manifestation of Maxwell's equations). The shape is ellipsoidal according to the structure of the electric permittivity and magnetic permeability tensors. Again, for the coupled propagation, the changes are very small.


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Next: Cross-coupled slowness surfaces Up: CHARACTERISTIC SURFACES Previous: ``Elastic'' slowness surfaces
Stanford Exploration Project
1/13/1998