Re: Ball lightning - Terry's thoughts....

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: William Beaty <billb@xxxxxxxxxx>

On Wed, 10 Aug 2005, Tesla list wrote:

> Original poster: Steve Conner <steve@xxxxxxxxxxxx>
>
> Woo Bill! I want some of what you're smoking! :-9 That
> has got to be the best explanation I've ever heard of
> how it works.

It all came from a single idea: what if we can see radio waves?  In that
case a painted metal plate would look like a near-perfect mirror.

> It makes me think that when we do these BL and melting experiments, we
> are using the microwave oven exactly like a vacuum tube Tesla coil.

Yep.  (But running at a high overtone frequency of the secondary, so you
get breakouts at many different spots.)  I didn't realize this until some
physics student claimed that microwave ovens couldn't produce corona,
since 500 watts RF doesn't give a wave with a high enough voltage to
trigger sparks.  Ah, but what if we aren't cooking a roast?  What if we
have a high-Q resonant waveguide?  In that case we might only inject
500watts... but inside the waveguide we'd have 100.5 kilowatts going out,
and 100 kilowatts bouncing back again, creating an immense standing wave
and huge electric currents in the ground connection, but with only
500watts being absorbed in the conductors.

So when performing microwave tricks for an audience, I tell people that a
microwave oven with no food inside is the same as a 2500 MHz Tesla coil.

> The only difference is that, on account of the waves being so short, we
> can make the secondary "coil" from a hollow piece of metal and put the
> breakout point inside! :-o And instead of "colossal discharges" that
> look like lightning, we get balls of white-hot plasma.

Ah, but the plasma balls are the same as a "power arc," and I know of one
way to produce lots of long thin streamers instead.  Fill a glass bowl
with argon and stand a sharp piece of metal foil up inside.  Use a violet
wand or a vacuum tester to verify that the pool of argon is pure enough
and supports long sparks.  Cover the top to keep the fan from blowing away
the gas, then nuke the bowl in a microwave oven.  Hundreds of lightning
bolts spew from the foil for a second or two.  Then it converts to the
usual "plasma flame" discharge.

Instead of a bowl you can use a small trash bag.  In that case the bag
melts and deflates, and sometimes the "lightning" spews out of the bag
along with the escaping gas.


(((((((((((((((((( ( (  (   (    (O)    )   )  ) ) )))))))))))))))))))
William J. Beaty                            SCIENCE HOBBYIST website
billb at amasci com                         http://amasci.com
EE/programmer/sci-exhibits   amateur science, hobby projects, sci fair
Seattle, WA  206-789-0775    unusual phenomena, tesla coils, weird sci