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Re: Ball Lightning from high-amp discharge
Original poster: westland <westland@xxxxxx>
The New Scientist just reported on lightning
balls created in the lab by two Brazilians
-- Antônio Pavão and Gerson Paiva from the
Federal University of Pernambuco in Brazil
(perhaps Antonio de Queiroz at UFRJ has met them)
... here's the text (and there are pictures at the article)
Ball lightning could soon lose its status as a
mystery, now that a team in Brazil has cooked up
a simple recipe for making similar eerie orbs of
light in the lab, even getting them to bounce
around for several seconds. Watch a movie of the
bouncing balls here. <http://www.espacociencia.pe.gov.br/multimidia.php>
Thousands of people have reported seeing ball
lightning, a luminous sphere that sometimes
appears during thunderstorms. It is typically the
size of a grapefruit and lasts for a few seconds
or minutes, sometimes hovering, even bouncing along the ground.
One eyewitness saw a glowing ball burn through
the screen door of a house in Oregon, navigate
down to the basement and wreck an old mangle,
while in another report, a similar orb bounced on
a Russian teacher's head more than 20 times before vanishing.
One theory suggests that ball lightning is a
highly ionised blob of plasma held together by
its own magnetic fields, while an exotic
explanation claims the cause is mini black holes
created in the big bang
A more down-to-earth theory, proposed by John
Abrahamson and James Dinniss at the University of
Canterbury in Christchurch, New Zealand, is that
ball lightning forms when lightning strikes soil,
turning any silica in the soil into pure silicon
vapour. As the vapour cools, the silicon
condenses into a floating aerosol bound into a
ball by charges that gather on its surface, and
it glows with the heat of silicon recombining with oxygen.
To test this idea, a team led by Antônio Pavão
and Gerson Paiva from the Federal University of
Pernambuco in Brazil took wafers of silicon just
350 micrometres thick, placed them between two
electrodes and zapped them with currents of up to
140 amps. Then over a couple of seconds, they
moved the electrodes slightly apart, creating an
electrical arc that vaporised the silicon.
The arc spat out glowing fragments of silicon but
also, sometimes, luminous orbs the size of
ping-pong balls that persisted for up to 8
seconds. "The luminous balls seem to be alive,"
says Pavão. He says their fuzzy surfaces emitted
little jets that seemed to jerk them forward or
sideways, as well as smoke trails that formed
spiral shapes, suggesting the balls were
spinning. From their blue-white or orange-white
colour, Pavão's team estimates that they have a
temperature of roughly 2000 kelvin. The balls
were able to melt plastic, and one even burned a hole in Paiva's jeans.
These are by far the longest-lived glowing balls
ever made in the lab. Earlier experiments using
microwaves created luminous balls
but they disappeared milliseconds after the microwaves were switched off.
"The lifetimes of our fireballs are about a
hundred or more times higher than that obtained
by microwaves," says Pavão, whose findings will
appear in /Physical Review Letters/. Abrahamson
is thrilled. "It made my year when I heard about
it," he says. "The balls, although still small,
lasted long enough to come into the mainstream of
observed natural ball lightning."
Pavão's team is currently working out the
chemical reactions involved in the balls'
formation, and experimenting with other materials
that might work too, including pure metals, alloys and sulphur compounds.
From issue 2586 of New Scientist magazine, 10 January 2007, page 12
Tesla list wrote:
Original poster: Mike <megavolts61@xxxxxxxxx>
in the lab. Tesla could supposedly conjure it up at will
The only reference that comes to mind is in CS Notes,
where he records it as an anomaly, worth of comment.
Is it noted elsewhere?
I read somewhere(darn my memory, I cannot cite
it) that he could produce electrical 'fire
balls' in his Houston street lab.
Supposedly, he could hold one in his hand and
then put it away in his pocket. Sorry I cannot
point to the reference on that.
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