sci.physics.electromag

On 22 mar, 14:41, "Szczepan Bialek" wrote:
>
>
> > Engineers from electron beam area should know that.
> > S*
>
> In my view, there is no way that they would not know this.
> But they rather use the term as involving some material
> support, for applied applications. Don't you think?
>
> But I still do not know if an electron beam in vaccum is like electrons in=
a
> superconductor (no grad) or like in a wire (with grad q). Maybe after
> Easter.
> S*

They are the same electrons, of course. Electron beams through
vacuum have been used, and experimented with for about 100
years. Look for Coolidge tubes, among others.

The main difference, from what I see, is that with free electron beams
as we can experiment with them, there is the acceleration factor
which probably higher than for superconduction in a cooled wire or
other material. In the latter, it seems to me (I may be wrong), that
the velocity of electrons may be somewhat more restricted than
for a free beam, each electron of which will accelerate as a function
of the inverse square of the distance to the anode the instant they
are pulled out of the cathode.

But I am no expert on this particular issue.

Andr=E9 Michaud