From: SFPhysics@aol.com
Date: Thu Dec 19 2002 - 22:54:21 PST
From: SFPhysics@aol.com Message-ID: <fd.214478d2.2b34189d@aol.com> Date: Fri, 20 Dec 2002 01:54:21 EST Subject: Adding to the Plasma List...and Plasma Sphere Implosion...
Much of our technology is enhanced by plasmas. We see dozens of plasma
devices every day without even thinking about it. Street lights that are of
the mercury vapor or sodium vapor type use a plasma discharge arc. The new
super bright auto headlights (the blue ones) are short arc plasmas. Every
time you go the movie theatre you are seeing light shown through the film
from a Xenon plasma arc lamp. Electronic flash units on photographic and
digital cameras use a Xenon plasma. The new flat television displays and the
flat computer monitors are plasma discharge devices. Clocks with the old
glowing digits (not LED types) and VCRs with complex flat displays are plasma
gas discharge devices. In short, plasmas are EVERYWHERE you look. By
daytime it is the sun so you just can't get away from them.
Leak detection on glass high vacuum tubing in things like cyclotrons and mass
spectrometers once used high voltage wands (Odin coils) to show where pinhole
(yes PINHOLE) leaks were. As the wand approaches the pinhole into the vacuum
chamber, the gas inside near the hole becomes a plasma, gives off photons,
and bingo you have found your leak. BUT, if the high voltage leak detector
were cranked up too high or you touch a thin weak point, it would actually
punch a microscopic pinhole in the glass, sometimes with catastrophic results.
As for the implosion of the Exploratorium plasma globe, assuming a globe
about the size of a basketball (approx. 26 cm) gives you a surface
(A=4pi*r^2) of roughly 2124 cm^2. Since 1 Atmosphere is roughly 1 Kg/cm^2
then the sphere had roughly 2124 Kg of total pressure on the surface. For
the sphere to implode in a surprise energy release all you need to do is
provide a pinhole (yes PINHOLE) by putting a sharp object such as the point
of a pin or a compass point on the surface of the globe. If a weak point is
found in the amorphous glass structure the resulting pinhole opens a current
path to the outside creating a hot spot which eventually expands to cause the
glass to break. I do it with lightbulbs on my 1 meter Tesla coil after a
scratch is applied to flaw the glass surface first ! ! ! Which raises the
question, how much power were you putting into the plasma sphere? I wouldn't
expect the output to have been that high.
Al Sefl
Gaining mass with the holiday season...
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