Re: Repulsion binds atoms

Ken S. Tucker wrote:

Edward Green wrote:
Ken S. Tucker wrote:

Edward Green wrote:

I have some funny ideas about "force", BTW, though I'm not trying to
develop them here.

Ok, so did AE.

Heh. Not _that_ funny idea. A different one.

Well I'm listening.

It's just this. Aside from forces which aren't forces (gravity), one
can form the impression there are real forces, and things which look
like forces, but express the creation of entropy; the rubber band
contracts, we say, even though contraction is energetically neutral or
even unfavorable for each uncoiled polymer, because of the
configurational entropy. I just wonder if this principle isn't more
universal, and perhaps there is really only one variety of force after
all: that is, force is always a shorthand for the ability to create
entropy, though sometimes where the entropy is being created may be
less obvious than in the configurational entropy of the rubber band.

An example may be provided by the coulomb force, considering the
attraction of two like charges. What will happen if the charges are
allowed to accelerate towards each other?

We agree on the answer to this one, they will radiate. And what does
this mean? That the energy of the system goes down? Not at all, of
course: the total energy stored in the field remains constant, but,
from a first situation where the stored energy is localized around the
static charges, some of the energy is literally radiated away to
infinity. It is very reasonable to suppose that the overall entropy of
the field increases. So at first glance may have looked like a static
force which had nothing to do with entropy in reality seems to express
a tendency to move in the direction of spontaneous change by increasing
entropy.

My guess is that the class of forces which are really a measure of the
potential to create entropy is much larger than usually thought, and
possibly universal.

<...>

Maybe it's
that old British Commonwealth comraderie... excluding, of course, above
referenced francophiles.

Well, england was occupied by the french in
1066 and it remains an occupied nation ruled
by aristocrats.

So the whole aristocratic thing in England is an echo of the Norman
invasion? Ironic that England also seems to have been the cradle of
the closest approximation yet to a society governed by the principle of
"equality".

Ken Muldrew, whom I already mentioned, I believe was tinkering with
some kind of quantitative theory of society in his spare time. One of
his themes was -- to express it in my own words and I hope not too
severely garble his -- a tendency for parasitism to approach an
equilibrium level. Another general theorem on society might involve
the tendency towards stratification: inheriting it from invasion is one
route, but start with as much egalitarianism as you can muster, and
probably class formation is inevitable.

<...>

But then you would want to ask about
"Electron Beam Lithography" or "Electron
Microscopes". I haven't found evidence
a pair of free electrons will radiate,

I don't follow you. Are you saying there is no radiation in these
devices associated with the spreading of the electron beams?

Yes, the radiation is nil, justas the radiation
of a current path in Super Conductor is nil.

At the risk of being obtusely persistent, shall I take it, at least for
the first two examples, that the beam spreads just about as would be
predicted for a given flux density of classical electrons travelling in
parallel, or is there some quantum effect which forbids this?

IMHO, I cannot knowledgeably explain a beam spread.

Am I
really wrong in thinking a pair of similar classical charges, free to
move apart from one another would radiate?

In order to adopt that belief, you would need
to have some understanding as to how a photon
or EM wave is emitted by that process, other-
wise I'd keep an open mind.

I thought of a crude argument why this might be correct: imagine a
spherical shell of charge, held at a fixed radius until time t_0, then
released to expand. To the best of my knowledge Gauss's law applies in
dynamic as well as static situations. Combining this with the
spherical symmetry, we conclude that the electric field outside the
expanding shell never changes in advance of the shell. What about the
magnetic field? We do have a blip of dE/dt as the shell passes, so I
suppose we also have a blip of H (a singular blip at that). But that's
it. No radiation.

That's a cool gedanken, but your dE/dt needs
a reference to measure that, and that in turn
will produce EMR.

I don't follow that. Forget about what happens at the interface, I
seem to have reached the conclusion that a uniformly expanding
spherical shell of charge will produce zero outgoing signal of any kind
-- never mind if we are going to qualify some signal as "radiation".
I'm not sure I believe this, but I can't find the flaw in my argument.
Can you?

<...>

But the two point-like charges lack this full spherical symmetry, and
I'm still not sure what happens qualitatively. Do we get a
cylindrically symmetrical disturbance whose distant field strength
falls faster than 1/r?

I think that depends upon how you measure
those effects.

Certainly whether there is radiation depends on a careful definition.
I'm certain there is some outgoing signal in this case, though it might
all qualify as "near field" or "evanescent field".

.

Relevant Pages

  • Re: Repulsion binds atoms
    ... "Electron Beam Lithography" or "Electron ... Yes, the radiation is nil, justas the radiation ... really wrong in thinking a pair of similar classical charges, ... expanding shell never changes in advance of the shell. ...
    (sci.physics)
  • Re: Repulsion binds atoms
    ... configurational entropy. ... That the energy of the system goes down? ... "Electron Beam Lithography" or "Electron ... Yes, the radiation is nil, justas the radiation ...
    (sci.physics)
  • Re: Alice slays Mad Hatter
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  • Re: Alice slays Mad Hatter
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  • Re: Is electromagnetic field theory unified?
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