Thanks for the detailed explanation, Jeff.
We share a common interest in exploring the different types of electrical
patterns in coils. I once produced a unique blue jet discharge with a
combination flat spiral and tall solenoid secondary. The blue jets were
more or less equally spaced and of similar lengths and discharged only in
the top hemisphere of the top load. In other coils I have seen the
perpendicular discharges you are calling phantoms, too.
My experience is flatter secondary coils tend to produce thicker and whiter
streamers, while taller coils tend to produce thinner and purpler
streamers. On any coil, the spark between the secondary ground and true
ground will be thicker and whiter, and the spark between the secondary coil
top and true ground will be thinner and purpler. This observation alone
indicates something is fundamentally different in the condition of the
electrons at those locations.
The coil geometry also determines the pattern of ambient magnetic flux
tubes in the immediate environment of the secondary. A strong dielectric on
the secondary will increase the E field strength surrounding the secondary.
The dominant environmental factors for determining streamer patterns seems
to be aerosol particles (dust), and humidity. The room I used for my
experiments had a layer of aluminum treated mylar on all the walls and
ceiling, which may have helped develop electrostatic resonance in the room.
The combination of magnetic flux patterns, E field, and ambient medium
determine the discharge patterns.
The quality of the resonance and the positions of the nodes in the
secondary also influence the streamer patterns. In the combination coils I
built, they were tuned to have one of the nodes where the two coils were
connected. It seems this was a major factor in producing the blue jets.
For the past five years I have been gradually building a new workshop and
home. I just finished it this last winter. I hope to get back to coil
engineering this year, along with several other experiments I have been
interested in.
If someone out there has a three D printer that can print a coil form about
8 inches by 48 inches, I have a special secondary I have been wanting to
build for the past ten years.
Dave Thomson
On Wed, May 21, 2014 at 10:40 PM, Jeff Behary <jeff_behary@xxxxxxxxxxx>wrote:
> Dave and David,
>
> The main difference here between regular Tesla coil corona discharges and
> so called "phantom streams" is that the later have very distinct fractal
> patterns in the air and
> aren't mere diffusion. The "Phantoms" as per Tesla's lectures were
> mentioned as perpendicular lines darting out a foot or more in all
> directions - this is what happens at moderate power levels. If you reduce
> the power to less than 50W and have certain other conditions correct (ie,
> the spark gap must fire slowly, and be adjusted in really small increments,
> the transformer/cap must fall within a range to allow the gap to fire
> intermittently, the topload must not be too big nor too small etc etc...)
>
> The positive streams - which are the most typical and easiest to acquire -
> have a really cool fractal pattern like this:
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_8035002824_large.html
> With a 200T pancake coil and 8-10mA neon (3-5kV) the discharge is faint
> but so intensely propagated that a 2" copper ball with produce the streams
> a foot or more
> radially in all directions - literally a 2 foot sphere of activity.
> If the gap is opened very slowly and precisely the sound of the discharge
> will change and the branches will grow to nearly a 1/2" in diameter yet
> retain the patterns - as in this photo:
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_7306920280_large.html
> At points if the gap is opened more, a negative oscillation or
> oscillations will appear interposed as this:
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_3652576312_large.html
>
> Normally the negative is smaller and slightly fish-tail in appearance:
> (A good example)
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_0260820729_large.html
>
> A pure negative discharge will normally only appear when dielectrics are
> interposed and induced discharges occur:
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_2390004612_large.html
>
> Occasionally the negative plumes have a curious shape like this:
>
> http://www.electrotherapymuseum.com/2012/Kinraide7MP/content/_6344063482_large.html
>
> It took a long while to decipher the why and how. I need someone with
> fancy gear. These baby neons, or regular neons when operated with a lot of
> resistance or a variac to limit the total power level to much less than
> 30mA (5-15 seem to work best) actually pulse the Pancake Coil with a messy
> DC - like an induction coil with a mechanical interrupter. For whatever
> reason certain settings of the gap produce just the right pulse to allow
> the very distinct formations in the air surrounding the terminal. Simply
> rectifying the output of the NST or trying to force the spark gap to
> rectify it (point - plate gaps, etc) can show a little of the effect but
> the strongest (and drastically surprising - like the 1/2" thick branches)
> happen without any real departures from the norm. The best as can describe
> it, the same way you can get mains resonance with any xfmr at specific
> power levels and cap sizes, you can also get a strange rectification of
> sorts when you combine a xfmr, cap, and s
> park gap
> . Even If you leave out the primary and replace it with a polarity
> indicating Geissler tube you can see it clearly, and with this later tube
> you can watch as one pole lights (showing the negative pole) and how
> adjusting the gap the polarity may suddenly reverse, or at certain
> intervals the discharge is purely oscillatory and on adjusting the gap one
> pole will be predominantly positive or negative...its really strange and a
> lot of fun.
>
> With cylindrical coils as Tesla used the fractals tend to be washed a lot
> into the straight lines, with pancake coils as Kinraide used it is much
> easier to produce the fractals and very distinctly produce them.
>
> Even on the video Frank Jones' old android phone (which is the only camera
> I've had luck to show these, including a $6000 borrowed UV camera with
> quartz lenses) you can only see about half of what the naked eye could see.
>
> One day we all must just meet for once and I can show you all in person.
> Its a lot of fun. I collected hundreds and hundreds of antique Tesla
> Coils, and while they were all a little different and interesting these
> Kinraide experiments were personally the most mind-blowing for me. I was
> fortunate to acquire the old glass negatives to strike my curiosity...to
> see them in person, 1890s, hold in your hand one of the original coils that
> made them, and then to see the actual discharges and hear the strange
> sounds of the spark formations, the sounds from the spark gap even, its all
> a really different side of Tesla Coiling, and different in a good way
> because at some point we all think we've seen it all and nothing can be
> better than witnessing the unexpected "live".
>
> This future museum project, well, this style of coil will be a special
> feature just for the coiling crowd. I won't have the biggest Tesla Coil
> but what I will have are coils that inspire people to try something new...
> one of the few TCML members that came to the house was David Sharpe... a
> great guy. I remember the look on his face a few times when he saw things
> he wasn't expecting. Like the 100T secondary coil from the Mcintosh Hogan
> throwing a hot purple arc about 10" long. We had a great laugh over that...
>
> The fun things about all of this stuff, even something as crude and simple
> as a spark gap Tesla Coil can take you off guard. When you operate a Tesla
> Coil with a 100kV X-Ray transformer, or a 16-plate Static Machine, or a
> 900V transformer and 1/2 mfd cap the outputs are as different as night and
> day!!
>
> Jeff
>
>
>
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