Re: Sparkles in the arcs

["Jim Lux" <jimlux-at-jpl.nasa.gov> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Many snips.. comments at end

> > > Original poster: "Ross Overstreet" <ross-o-at-mindspring-dot-com>
> > >
> > > Hi,
> > > I was playing around with building fires on top of my toroid this
weekend
> > > when I stumbled across an interesting effect.  Burning cardboard
apparently
> > > liberates lots of carbon particles that make bright sparkles in the
brush
> > > discharge of a TC running at low power levels.  My photo didn't turn
> out too
> 
> powering up.  Can't remember what the Corums used... 
> > 
> > VERY interesting!! These look very similar to the "ball lightning" that
> > the Corums photographed off their system. Carbon particles are the

I've spoken with Jim Corum at some length about making ball lightning and
"death rays"...

They've used a variety of techniques to get the sooty flame... carbon rich
hydrocarbon gases seemed to be the most popular (acetylene, propylene, and
MAPP spring to mind).  They also experimented with carbon black and an
aspirator arrangement with an RF driven quarter wavelength coaxial line. 
They also fooled with blowing streams of metal particles from within the
topload.

They started with some simple calculations that show that for observed BL
lifetimes, you can't have enough heat stored in a simple plasma (it
radiates the energy away and cools too fast), so you need something to keep
it going, i.e. incandescent carbon, metal particles, or something.


When I worked in the effects biz, we used to use napthalene and diesel fuel
to make that really black smoke you see in the movies for "oil fires" and
"car falling over cliff and blowing up" . Don't breathe the fumes... the
sublimated napthalene is really, really unpleasant... for days later, even
if does form very  pretty crystals as it crystalizes out in the air. 
Benzoyl Peroxide also gives a nice black sooty smoke (and a really good
orange fireball to boot), but is a serious safety hazard. And, there is
always the traditional standby, burning rubber tires (but hard to
extinguish).  You might also  try rubber cement (the solvent, mostly
pentane and hexane, burns quite well and helps the rubber to stay
ignited.)... lots of black smoke. What about burning sulfur and charcoal
(what they used in the Wizard of Oz.. back when effects techs were "real
men" and didn't mind coughing up blood for days later)