Re: Question 07/02 CURRENT IN A WIRE

[Hugh Haskell <hhaskell@MINDSPRING.COM>]

At 15:10 -0500 11/19/02, John S. Denker wrote:

> Hugh Haskell wrote:
>
>  > In a plasma,
> >  there is motion between the opposite charged particles (IIRC a plasma
> >  is only a "plasma" if it is at least approximately neutrally charged,
>
> Mostly irrelevant.  Certainly not the whole story.
>
> >  in otherwise empty space, a beam of charged
> >  particles will not sense a magnetic field due to the presence of
> >  other charges in the beam,
>
> That's a frame-dependent statement.
> The physics is frame-independent.
> The correct frame-independent statement is that the
> particles interact via the electromagnetic field.
> Deciding whether the field is "electric" or "magnetic" is
> frame-dependent and not particularly important.
This is exactly why I am a bit perplexed over this and have been for
a long time. If whether the effects we are talking about are electric
or magnetic depends on ones point of view, the results should be the
same in either case. For example, the parallel beams in a vacuum that
I just mentioned in another posting. What we know is that, when we
look at two parallel currents in wires, that the force between them
is attractive if the currents are in the same direction. But the only
thing I can see between two parallel electron beams is a repulsive
force. That shouldn't be frame dependent, either. I admit that my
understanding of this is not nearly what I would like it to be, so I
look forward you your explanations.

Hugh
--

Hugh Haskell
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<mailto:hhaskell@mindspring.com>

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