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Re: Strange Phenomenon In DC Powered VTTC

Original poster: William Beaty <billb@xxxxxxxxxx>

 Original poster: "Cameron B. Prince" <cplists@xxxxxxxxxx>
 >  I was playing around with the discharge drawing arcs. I noticed
 > you can start an arc on the side of the torroid and it will begin to swirl
 > around the side of the torroid like a little tornado. This continues after
 > you pull away and I've seen it continue to run for almost a minute. This
 > is while the primary discharge output from the electrode continues.
 > It's a really neat display. I tried to capture it with my camera here:
 > http://www.teslauniverse.com/members/cprince/images/dc_vttc/DSC00127.JPG
 > Have any of you seen this before?

I wonder if the hotspot on the metal is acting like a diode (or more
likely, acting as an old style mercury-vapor rectifier.)  If so, then
there must be quite a bit of DC in the corona, and it might respond to
magnetic fields.  The Earth's magnetic field is diagonally upwards if you
live up at high northern latitudes, and it should make a DC corona
discharge start spinning around.

Try sticking a big Neodymium magnet on the end of a rod and waving it over
the discharge.  It might make the discharge move oddly.  (Also try
reversing the magnet poles to see if it will push the discharge in the
opposite way.)  Also: if there is DC in the discharge, then if you stand
near it, you should feel cold air pouring out of the plasma (just like
with a VandeGraaff with a sharp wire attached to its sphere.)

Speaking of rotating DC streamers, I once had one of those "plasma mug"
devices bought from Spencers Gifts.  If a neo magnet was held within the
mug, the streamers inside the mug would spin rapidly around the rim...
and if the magnet was turned upside down, the streamers would spin the
other way.  It's an electric motor!  Or more like a Faraday Disk, or
perhaps an MHD-based liquid metal pump.  But with its conductors made of
plasma!  And obviously there must be quite a bit of DC inside the neon
streamer in the glass mug.  But also something weird is going on: where
are the slip rings?  And where is the return path of the DC circuit?  The
return path must be invisible, made of ions drifting through the low
pressure gas.

(((((((((((((((((( ( (  (   (    (O)    )   )  ) ) )))))))))))))))))))
William J. Beaty                http://staff.washington.edu/wbeaty/
beaty@xxxxxxxxxxxxxxxxxxx       Research Engineer
billb@xxxxxxxxxx                UW Chem Dept,  Bagley Hall RM74
206-543-6195                    Box 351700, Seattle, WA 98195-1700