Re: Science fiction or a wrong model again.

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

One thing is clear, electrons will start escaping
the wire as soon as their kinetic energies become
larger than several eV (work function). Unless
the loop is perfectly circular (or a solid block
like a vacuum container) and a changing magnetic
field is applied to keep electrons on a circular
orbit. Under such conditions, I think, that electrons
could be accelerated up to energies at which a gain
per loop becomes equal to a loss per loop due to the
synchrotron radiation. The frequency of that
radiation will depend on the diameter of the loop.
Will I have a chance to debate these issues in the
general physics course? Probably not.
Ludwik Kowalski

----- Original Message -----
From: Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>
Date: Tuesday, January 8, 2002 1:17 pm
Subject: Science fiction or a wrong model again.

> Jack wrote:
>
> > This relativistic effect has come up twice
> > in my life. Once was in my Ph D oral exam
> > (I answered correctly), the second was in
> > a patent application I wrote ...
>
> Is this patentable, Jack? Consider the most
> simple circuit loop: a long wire and a
> source of emf, such as the secondary
> winding of a transformer. The potential
> energy gained in the source is used to
> accelerate free electrons between collisions
> with bound atoms of the wire. It is then
> thermalized. But suppose that the entire
> loop is made from a semiconducting wire. In
> my naive model electrons would no longer
> collide with atoms. They would circulate
> the loop with a constant speed if the primary
> of the transformer was off. Right or wrong?
>
> But with the transformer is working. Therefore
> electrons should gain kinetic energy when the
> emf is positive and loose it when it is
> negative. In other words they can be accelerated,
> like in a betatron. At f=100 Hz electrons are
> strongly accelerated for two or three ms during
> each cycle. That is sufficient to make a very
> large number of round trips. Where am I wrong
> this time?
>
> Suppose the average accelerating emf is 10kV.
> How much energy will electrons gain after
> making only 100 round trips? One million eV;
> they will become ultarelativistic. Suppose
> the loop also contains an element in which
> superconductivity can somehow be destroyd at
> the end of each accelerating cycle. This
> element would then act as an anode in an x-ray
> tube. By controlling the frequency, and the
> averge accelerating emf, one can create a
> very flexible x-ray machine. The ironless
> transformer could be used to avoid practical
> complications (keeping the secondary at the
> very low temperature).
> Ludwik Kowalski