Re: Displacement Current Demonstration

On Wed, 21 Mar 2007 16:13:47 GMT, "Bill Miller"
<BillMillerKT4YE@xxxxxxxxxxxxxxxx> wrote:

Hello Benj...

You don'yt have to decode the .gif files. I did a re-posting of the
derivation. I apologize for the inconvenience, but I did not know how to
imbed equations in a posting. Now I do!

Part of the problem with Displacement Current is that the magnetic field
supposedly associated with it is *very* weak. All the "derivations" that I
have seen set out to "prove" that the magnetic field inside the gap between
two capacitor plates is the same asit if the gap had been filled with a
conductor.

But in a real capacitor, the gap is extremely small. So the task is to
measure the (supposed) magnetic field inside the gap (a mm or so in width)
in an environment containing meters of wires containing magnetic fields
caused by the exact same current's frequency and phase. This task makes
finding a needle in a haystack seem trivially simple by comparison.

Enclosing the capacitor in a black box and attempting to measure what is
inside seems doomed to failure. Magnetic fields from the capacitor would
meld together with fields from the connections such that it would make the
task of measuring H inside a capacitor look simple!

And yes, I am convinced that the shape of the capacitor will control the
shape of the fields. That's what my post labeled "Field Finder Software" is
all about. So far, I have received no replies. #SIGH#

Bill
"Benj" <bjacoby@xxxxxxxxxxx> wrote in message
news:1174429514.720323.176860@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Bill Miller wrote:
Hello Benj...

If Displacement Current is not the *cause* of a magnetic field, thus
satisfying the well known Dell cross H = J + dD/dt, then where the *H*
does
the H come from?

It appears that it comes from the motion of charges as they are drawn
toward
the surface/"pushed" away from the surface by the E field. I have put
together a fairly short description of what happens in a capacitor and it
is
shown below: (I think... I've not tried to append rich text before.)

Forgive me that I haven't yet decoded your .gifs and followed your
arguments, but I still want to comment before I do that.

Yes, the question where indeed does the H come from. And it's worse
than that. If you look for example in a textbook like Plonsey and
Colin you'll find the usual statements that that if you have a "black
box" with a capacitor in it and you measure the magnetic field about
it, you can't tell what kind of capacitor is in there even though
Ampere's law fails if you compute it through the gap of the capacitor.
The displacement current is supposed to make the whole thing work.

So the question in my mind is indeed where does the H come from and
furthermore, if it comes from charge motion on the capacitor plates,
shouldn't it then create a magnetic field outside the "black box"
which is dependent upon the GEOMETRY of the given capacitor rather
that the implied "can't tell what's in the box" scenario?

These were the musing that got me wondering if indeed anyone had
actually tried any of these displacement current "black box"
experiments and tried to see if a field was indeed generated
independent of the capacitor geometry? And especially if an H field
can be generated in free empty space from a changing E field which is
the theory behind electromagnetic radiation. What kind of mechanism
can we imagine that would do that?

Benj

Has no one looked at my permittivity paper at
http://www.dualspace. net? It answers all the questions and does away
with any idea of electrons on plates.

The paper shows that eps0 of 8.8uuF/meter can ONLY be accomplished in
a vacuum if it (effectively) carries electron pairs constrained to
center with spring constant K = 2.6e14N/m and electron pair density
rho = 7.2e21 C/m^2 so that
eps0 = 4e*rho/K = 8.8uuF/meter
in other words eps0 is proportional to double charge e and also to
double charge population rho, working against spring constant K.

The electric field causes the particles to lean left and right
respectively,thus letting the current move in the wires, their
velocity being displacement current.

I admit the paper is not easy reading, as I always try to work things
out from scratch.
If Einstein (and Dirac) had known about permittivity they would have
come up with an entirely different theories. eps0 only was adopted
officially in 1960 in SI units. cgs writes off permittivity, but thus
loses the use of coulombs, getting instead esu's whose units are
volt-meters (work it out). Then to get force they have to multiply by
"Coulombs Constant) 1/4pieps0, which is just a way of bailing out one
of the esu's that has swallowed 4pieps0 so as to make it an honest
coulomb again.
John Polasek

.

Relevant Pages

  • Re: Displacement Current Demonstration
    ... Part of the problem with Displacement Current is that the magnetic field ... have seen set out to "prove" that the magnetic field inside the gap between ... But in a real capacitor, ...
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    ... If Displacement Current is not the *cause* of a magnetic field, ... It appears that it comes from the motion of charges as they are drawn toward ... together a fairly short description of what happens in a capacitor and it is ... The displacement current is supposed to make the whole thing work. ...
    (sci.physics.electromag)
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    ... A changing magnetic field in the evacuated (or ... >>> gap. ... > A *stationary* electron is moved by a magnetic field? ... >> magnetic dipole magnet to change its magnetic field? ...
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