Do two parallel electron beams attract?



This question is doomed to remain hypothetical, since there seems to exist no set up allowing to focus two separate parallel electron beams withing the same guiding E and B fields.
If you calibrate your fields to have an electron stream to be correctly focussed, then you can have only one beam in the fields.
Ref: "Principles of Charged Particle Acceleration", Wiley & Sons, by S. Humphries.
Andr Michaud
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What do you think about this: http://en.wikipedia.org/wiki/Z-pinch
That seems to imply that the fields

Plasma contains electron beams. S*
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Szczepan Bialek wrote:

Um. Yes! I had forgotten about Z-pinch in plasmas. Obviously there is something going on here that needs some thought. The current in a plasma actually DOES produce a self-focusing effect! Of course it's not particularly stable much to the dismay of the early fusion people, but that is of no consequence to the discussion here.
So what we observe so far seems to be:
1. electrons in a beam do NOT self-focus. This implies that the magnetic field is moving with the electrons so that a reference frame attached to the electrons won't see any anomalous magnetic fields arising from electrons that appear to be at rest.
2. A MIXTURE of positive (ions) and negative (electrons) in a plasma DO self-focus. This somehow implies that the magnetic field generated by current through the plasma is able to act back upon that plasma to compress it.
3. A MIXTURE of positive (protons) and negative (electrons) charges in a WIRE also are able to create a magnetic field which apparently is not moving at the velocity of the basic charged particles. If wires were like hollow tubes which electrons fired down then wires carrying current would NOT attract! As it is, we know that electrons in metals are bouncing around in there like mad and only move forward with a drift velocity. Somehow this fact allows magnetic motional forces to exist between the wires. And indeed I believe that there are observed "self-focusing" effects of a sort which is the current distributions found in heavy current DC bus bars due to the internal magnetic fields.
Therefore it seems to me that there are two situations here. One is the pure case of electron beams and the other are the cases of charged particles bouncing around in a mix in plasmas and inside wires. Methinks there could be some fundamental physics here!
Good point, Szczepan!
Benj
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wrote

It seems that electrons in a beam behave according to the current density. See the pages 18 and 19 (Alfven current) of::
http://deposit.ddb.de/cgi-bin/dokserv?idn 2318054&dok_var&dok_ext=pdf&filename2318054.pdf

It should be also density dependent.

".. heavy current DC" = The current density which give a noticeable effect.

I try to be constructive. S*
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