Re: Coulomb and Lorentz Gauge

From: jahn (suzysewnshow_at_yahoo.com.au)
Date: 11/06/04 

Date: Sat, 6 Nov 2004 09:41:16 -0500

"Androcles" <dummy@dummy.net> wrote in message news:49_id.39268$Bk6.32009@fe2.news.blueyonder.co.uk...
>
> "jahn" <suzysewnshow@yahoo.com.au> wrote in message
> news:2v0ql0F2djufbU1@uni-berlin.de...
> :
> :
> : > > : > In this evacuated cavity,
> : > > : >
> : > > : > +
> : > > : > __
> : > > : > N | o | S
> : > > : > ¬¬
> : > > : > -
> : > > : >
> : > > : > I have an electron 'o' which will accelerate to + and
> because
> : it
> : > > : > is a spinning bar magnet
> : > > :
> : > > : No... It will accelerate from + to - because it has a negative
> : > > : electrical charge.
> : Yeah BLUSH. I got that back'areds.
> : > >
> : > > Good grief! I could have sworn electrons were little balls with
> : minus
> : > > sign painted on the side and the *anode* of my TV tube had a red
> : wire
> : > > connected to the LOPT. What do the electrons do, wait for the
> right
> : > > moment to jump through the shadow mask and run off to cuddle
> : > > mama cathode? :-)
> : > >
> : > >
> : > >
> : > > : A positron will move the opposite way but it is also a
> spinning
> : bar
> : > > : magnet.
> : > >
> : Sometimes I get my left and right confused so rather that digress
> into a
> : discussion about which is which let me simply restate more
> ambiguouly:
> : The electrons accelerate because of their charge (Coulomb) , not
> because
> : of their spin (magnetism).
> : CRT's can employ either electrostatic (o-scope) or magnetic
> deflection
> : (video monitor). When magnetic deflection is used the interacion is
> : mainly between the deflection coils and the beam current, not the
> tiny
> : "spin current" of Stern-Gerlach and Zeeman fame. ;-)
> :
> Ok :-)
> Now, WHY does a magnetic field deflect a beam, but not a stationary
> electron?

The short answer is that one pole pushes with the same force that the opposite pole pulls... but we know more than that:

Excuse my wind... but try this.
Jack up the back of a RWD car and run the motor fast in hi gear.
The magically frictionless differential will permit one wheel to remain stationary but wind vortices will couple the wheels and
cause them to synchronze anyway. For a short axel, that is the condition of least turbulence.
Now we slit a rimless tire so we can put it betweeen the driven wheels and glue it back together. The big rim hole gives it 3 axes
of freedom for a limited range. Magic gimbelisers keep it from resting on the axel like a bracelet on an arm.
The planes of the outer wheel are fixed to be parallel by the bearings but let's release the inner tire so it's plane is not
parallel to the outer tires. It is mis-aligned. The vortices are going to spin up the inner tire, just as they did each other but
it will be wobbling like a swash plate[1] .
How long will it take the inner tire to figure out there is less turblence if it uses it's extra degree of freedom to line up with
it mates and stop wobbling like a swash plate? (Rhetorical! That ASCII math makes my eyes go crossed so lets just say about 15
seconds )
Path of least resistance wins every time.
Maxwell didn't really have a fluid and we don't really have air but you can see how it's not a bad analog for some kind of swirling
Coulomb field.

[1] Dirk will think any knowlege of helicopters is further proof that I am Dennis ROFL
de Oppresso Libre
http://www.specialoperations.com/Foreign/Australia/pic77.jpg

Since the axel corresponds to a magnetic flux line and Bournoulli's principle might not have a Coulomb equivalent we know from nails
and wires that the magnetic force will causes the outer tires to move inward just as wire wrapped on a nail will bunch-up when we
connect a battery.
Hmmm... I suppose Bournelli's principle predicts the same thing but I won't take that leap of faith.

That doesn't really answer you're deflection yoke question but it lay's a little groundwork
Recall, we can't simply account for the deflection resulting from the beam current but must also account for the target spread
resulting from the spin current. (Zeeman, Stern-Gerlach)

Ok... The beam current is perpedicular to the wire in a focusing magnet and parallel to the wire in a deflection magnet. So Ampere
or Lorentz parallel force laws explain the greater deflection component. Each electron path, takes on a helical component resulting
from the interaction with it's spin with the deflection/focusing magnets. The effect is apparently too small the justify the shadow
mask in a VDU but in electron microscopy and semiconductor fabrication it is an important consideration in mask design.

> Or is there a way we can show that it does? I was thinking
> along the lines of Millikan's charged droplet falling under gravity
> (before you diverted attention to the photelectric effect) and
> Brownian motion.
> http://chem.ch.huji.ac.il/~eugeniik/history/millikan.html
> "The apparatus associated with Millikan's oil-drop experiment is shown
> in the figure (left). A closed chamber with transparent sides is
> fitted with two parallel metal plates, which acquire a positive or
> negative charge when an electric current is applied. At the start of
> the experiment, an atomizer sprays a fine mist of oil droplets into
> the upper portion of the chamber. Under the influence of gravity and
> air resistance, some of the oil droplets fall through a small hole cut
> in the top metal plate. When the space between the metal plates is
> ionized by radiation (e.g., X rays), electrons from the air attach
> themselves to the falling oil droplets, causing them to acquire a
> negative charge. A light source, set at right angles to a viewing
> microscope, illuminates the oil droplets and makes them appear as
> bright stars while they fall. "
>
> Could we suspend the droplet with a magnetic field?
Is sounds difficult. Liquids and gasses like randomized magnetic domains. MHD passes a current through the liquid to interact with
the magnetics so some type of multicoil AC Helmholtz gizmo might be a possibility.

Most folks just spread a drop cloth or some old newspapers when they are concerned about falling oil dropplets. ;-)
 Sue...

> Androcles
>
>

"Androcles" <dummy@dummy.net> wrote in message news:ui3jd.40514$Bk6.17625@fe2.news.blueyonder.co.uk...
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