Cecil,

You've set up a false dichotomy here. When I, and others, write "The
electric field is the superposition of a forward and reverse traveling
wave" maybe it would be better to say "The electric field has two
terms, one that appears to be a forward traveling wave and one that
appears to be a reverse traveling wave." or something like that.
There's one electric field vector and one Poynting vector. Or there
are two. The structure of the electric field and the structure of the
real part of the Poynting vector both admit BOTH explanations of what's
happening.

You're not gonna get 300J in your one second line.... the stored energy
flux in the line depends on the wavelength of the incident RF, and in
retrospect, you might expect this from the fact that a misterminated
line goes through cyclical impedance variations as you change its
length (something that I know you're quite familiar with :-) )

I think the energy density per unit length in the line is proportional
to the Poynting vector (or it's integral over the cable cross section,
and the proportionality constant is the group velocity of the waves, I
think) I left Jackson at work, so I'm not certain right now. What I
am certain of is that you can't take the energy in the forward wave and
add it to the energy of the reflected wave and get that there are 300J
in a 1 second line carrying a 200W forward wave and a 100W reverse
wave. Rather, there's a 100W net forward power flux and THAT will give
you the energy contained in the part of the field that's actually
moving from source to load. The energy contained in the reactive part
has an integral that's going to cyclically vary with the length of the
line, and sometimes goes through zero (kL or kL - phi equal to an
integer multiple of Pi... or any integer multiple of a half wavelength,
which happens to be the length of an impedance repeating line, eh?)



Dan