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Re: Displacement current- is it real (was 7.1Hz)

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

At 08:55 AM 7/19/2005, you wrote: 
> So with your
> indulgence, I will make a
> few observations regarding criteria that must apply
> to displacement
> currents.

Stork, I guess I agree with every assertion you made
except #4.

> 4.  No magnetic fields are experimentally measurable
> in dispalcement
> currents in dielectrics.

But I don't really disagree with #4 either. I just
don't know whether it is true or not. When testing it,
I don't know how you would separate the (supposed)
field due to the displacement currents, from the
fields due to the conduction currents feeding the
plates of your test capacitor.

Maxwell himself seems to say that #4 is false, as one
of his equations is:

curl H=J+dD/dt

suggesting that displacement currents (dD/dt) create
loops of H-field just as if they were conduction
currents (J). Indeed this is the argument for how
radio waves propagate, with H-fields turning into
E-fields and back again as they fly along.

I would also agree that electrons do not jump between the plates of a capacitor to make a conduction current. The electrons are crowding at the plates glowing and hissing at you wishing they could jump across. But the fields have read the book and follow the rules anyway ;-))

In radio waves, the electrons really don't have to move far, they only have to wiggle around, so displacement currents could act far more as told.

Maxwell's displacement current idea is rather unique in that it is probably not quite right, but very difficult to prove wrong. The equations simply works for all cases...

Even our streamer models are totally dependent on them. In the case of a high voltage streamer, the displacement currents are perpendicular to the normal conduction currents so maybe they would be easier to look for there. A spark between two already charge spheres gets rid of the return current path problem. With Tesla coils, our displacements currents are for from subtle so we have and advantage over some of our lab friends trying to find them with a microscope ;-)

Perhaps discharging a charged sphere with the detector 90 degrees out from the conducted currents is a good place to look. Perhaps look inside the sphere (or long cylinder). It seems like there would be a physical case where you could find an anomaly. But Maxwell's pen might have indeed been mightiest of all and simply eliminated all such experiments form having positive results.

It will be figured out someday (probably soon), but I think it will be our atomic physics friends who can mess with electrons on the sub atomic level... Maybe they can take a pound of electrons and separate them into massless jars of E-fields and B-fields... Maybe they can separate out just the displacements currents and sell them to us to pour through our coils just to tease us >:-) But it seems on the macro atomic scale, there is not a whole lot we can do to bend Maxwell's rules...


I don't care what Paul Nicholson says, I'm off to wind
a big Rogowski coil and shoot some displacement
current through the hole in the middle :)))


I am sure you will detect them just fine :-)))

Cheers,

        Terry



Steve Conner