No, I'm just trying to figure out how an EM wave can have E and/or H
fields whose directions aren't transverse to the direction of
propagation (as in a lossy medium or in a hollow waveguide) can have
another property of "vibrations" or "oscillations" that *are* always
transverse. The properties of E and H fields that I'm familiar with
include orientation of the field in space, and change in amplitude with
time (which is what I'd normally call oscillations). And, of course, the
orientation can change in time also, as in elliptically or circularly
polarized waves. The property of "vibrations" or "oscillations" that
have a direction different from the direction of the field is new to me.

I notice that you're now qualifying your statement to free space and
isotropic media. Does this perhaps leave open the possibility that waves
in a lossy medium, or bounded within a hollow waveguide, could have
"vibrations" that *aren't* transverse to the direction of propagation?
My original question was in response to your statement that EM waves
were always transverse, regardless of the medium.

Do you perhaps have Krus' _Electromagnetics_, or electromagnetics texts
by Holt, Johnk, Skilling, Magid, Magnusson, or Jordan & Balmain? If so,
perhaps you could direct me to a section which addresses this.

Roy Lewallen, W7EL

Peter O. Brackett wrote:
Roy:

[snip]

Do the "vibrations" of electromagnetic waves you referred to in your
previous post have another name?

Roy Lewallen, W7EL

[snip]

Oscillations perhpaps?

I don't really understand your question... do you object to the term
"vibrations"? What would you prefer, oscillations, or...

It is well known by Physicists that lectromagnetic waves [at least in free
space and isotropic media] are generally consist of only transverse
vibrations,. this type of vibration is inherent in the formulation and
solutions to the Maxwell-Heaviside equations.

For examples of longitudinal or compressive vibratons for instance in a
taught wire like a guitar string, transverse vibrations or oscillations are
side to side, but longitudinal or compressional vibrations would be the very
tiny vibrations in the length of the guitar string. In systems where
longitudinal vibrations are supported, generally the velocity of propagation
of longitudinal vibrations will not be the same as that of transverse
vibrations.

For a detailed explantation of compressional-dilutive or longitudinal waves
in a variety of physical systems, cfr:

William C. Elmore, and Mark A. Heald, "Physics of Waves", McGraw-Hill, New
York, 1969.

--
Peter K1PO
Indialantic By-the-Sea, FL.