On 26 Dec, 19:45, "AI4QJ" wrote:
"art" wrote in message

...

" To me, this suggests that the return path is
down the center which is resistive only. My prior post
states that it is possible for current flow down the
center of a dimagnetic material which was the case
in a barium cloud.
From the above in then becomes logical that RADIATING
surface length is what counts and thus a helical antenna
must have a counter winding to be resonant AND in equilibrium.
So the main pont is, what exactly stops current travel down
the center of a radiator to conform with every day thinking?"

At AC, it is established knowledge that skin effect takes place in round
diamagnetic conductors such as copper and aluminum. Skin effect happens as a
result of Lentz's law. From Lentz's law, foucault currents are set up to
oppose the magnetic field of the AC current sent by the generator. The
result is net forward current existing on the 'skin' of the conductor with a
net reverse current inside the conductor. Think of the inside of the
conductor as being occuppied by a current moving back towards the generator
that sets up a magnetic field which opposes the magnetic field from the AC
current sent by the generator. So you can see that indeed there is current
flow through the center of the conductor; it will be a weak current but it
is nature's attempt to oppose the change in magnetic field. I think the
situation you are speaking to is having additional currents through the
center that are additive (or subtractive) to the foucault currents. With
proper material selection (such as mu-metal, a magnetic material of very
high permeability), it may be possible to maximize the foucault currents
themselves to nearly cancel the applied magnetic field ( from the current in
the generator). I believe it would be truely a pioneering effort to have
center currents above and beyond this value, or cancelled, or even reversed.
I would never say that it was impossible; after all, what is mu-metal but a
material engineered and manufactured by man to increase its permeability
several times and which has the effect of greatly reducing skin depth
several times, thus allowing for maximum foucault currents even at low
frequencies. Could this occur with diamagnetic materials as well? I will not
say no. *I am not sure if it has ever been tried. Could the complete
mitigation of skin effect increase the velocity factor close to c in a
vacuum? Maybe. What if you could actually reverse the skin effect? That gets
into the things you are thinking about, i.e, smaller antennas. This is well
outside the normal scope of thought but it is interesting to consider the
'what ifs' and that sort of thing does not violate Maxwell, it merely
extends the applicability of Maxwell, Lentz etc..

Thanks for the detailed response. A lot of new stuff
there for me to follow up on,a new word too.
The bottom line is how can one prove which path the
current takes when it reaches the top of an antenna?
Art