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Re: Longitudinal E-waves ?

Mojca Cepic wrote:

In anisotropic materials normal to the wave front is not in the
same direction as Poynting vector or direction of the energy flow.

How can it be without bending of light rays? For any direction
the wave velocity and the group velocity are identical because the
source is said to be ideally monochromatic, only one f. The energy
flow (Poyting vectors), if I understand the topic correctly, must
be perpendicular to elliptical wave surfaces. Therefore ordinary
waves "carry energy" along straight lines but ordinary waves
"carry it" along curved lines. I am not saying that this actually
happens, only that this is a logical conclusion I am reaching.
There must be an error in my logic. Where is it?

The initial message, posted last week, is reproduced below.

************************************************
Consider an ideal monochromatic point source of light (one
frequency f) located inside a transparent material such as
calcite or quartz. Then focus your attention on extraordinary
waves whose phase velocity, v, is different for each direction.
The wave surfaces of that light are ellipsoids of revolution.
The wavelength, L=v/f, is different for each direction. The
source is located midway between the foci of moving wave
surfaces. Therefore the rays (call them directions of energy
transfer, or Poyting vectors, if you prefer) are clearly not
perpendicular to wave surfaces, except along the axes of the
ellipsoids.

Does this imply that electromagnetic E-waves may have
components parallel to directions of propagation? If this
were true then we would say that the waves are "partially
longitudinal". The only way of avoiding this silly conclusion
is to make an equally unacceptable statement that "the rays
of E-light are bending" inside the crystal.

Where am I wrong? Please note that the wave velocity and the
group velocity are expected to be identical (for each direction)
because the source is said to be ideally monochromatic.
Ludwik Kowalski