Re: TC Sparks and Arcs (Was - High Voltage Snubber caps

["Bill Lemieux" <gomez-at-netherworld-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

On that fateful day 8/5/00 7:25 PM, thus spake Tesla list:

> Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> 
> 
> Jim -
> 
> It is my understanding that the best man made vacuum on earth still has
> millions of atoms in the chamber compared to outer space.

 I believe your understanding is incorrect.  However, we need to define
"outer space".  If you are talking about an area within a few million miles
of a star or planet, such as most places within the solar system, then I'm
fairly certain you're incorrect.

If you are talking about inter-stellar space, you might be correct.

 With modern ultra-high vacuum systems, it is quite possible to achieve
"clean" vacuums with very few stray atoms, although it takes a while, since
you have to wait for the atoms to wander into cold traps, etc.

 As far as "millions of atoms in the chamber", what size chamber?!!  This is
a non-useful statement.  Millions of atoms remaining in say,
Lockheed-Martin's space simulation chamber at Waterton, Colorado would be a
great achievement indeed.

 Millions of atoms remaining in a one cubic foot chamber I could probably
achieve in my garage, if I were sufficiently determined.

 If you're going to talk about vacuum, you need to use useful terms, such as
Torr.  Typically, high vacuum is expressed in very small fractions of a
Torr, ie; 1x10 !-6 torr.  760 torr is one atmosphere.

> This may make
> sparks possible on earth depending on the amount of man made vacuum.

What does this sentence mean?  I am fairly certain that sparks are possible
on earth, because I think I was standing on earth the last time I made some
sparks.

> However, in space with the two isolated and energized terminals a distance
> apart a spark would be impossible at any voltage because of the better
> vacuum. Is this correct?

It depends on the pressure.  When going up into space from the surface,
there is _no_ altitude anywhere at which the atmosphere abrubtly stops, and
you suddenly have pure vacuum.  The pressure gradually drops lower and
lower, even past the point where a standard, garden-variety pressure gauge
or barometer would read zero.  At that point, it becomes more useful to talk
about "partial pressure" or "degree of vacuum", since you are no longer
dealing with "mass flow", but "molecular flow".

Once you have a significant space between the molecules, you won't have a
"spark" (ie; a heated, ionized channel in a gas), but a glow discharge.
Once that space becomes great enough, even the glow discharge will cease,
yet current may continue to flow, invisibly.

 This is not all or nothing process- the sparks don't abruptly stop, nor
does the glow discharge- the phenomena reduce gradually as the pressure
changes.

> I agree that arcs would be possible in space and this is one of the
> important differences between sparks and arcs. I think of sparks as a high
> voltage phenomena and arcs as a low voltage phonomena. In other words the
> initiation of the spark requires voltage while the arc requires current.

You will find it difficult indeed to achieve current flow at low voltages in
a vacuum.

> What do you mean by "it would be formed by being "drawn". Are you suggesting
> a spark has a force? I am not familiar with that concept.

If you believe that sparks do not exert force, perhaps you should re-examine
the phenomena of natural atmospheric lightning.

- Gomez (Bill Lemieux)

.........................................................................
"We cannot live only for ourselves. A thousand fibers connect us with our
fellow men; and along these fibers, as sympathetic threads, our actions
run as causes, and they come back to us as effects." -Herman Melville