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Re: Plasma coil?

>>From pgantt-at-ix-dot-netcom-dot-comThu Oct 31 21:44:59 1996
>Date: Thu, 31 Oct 1996 02:11:55 -0800
>From: pgantt-at-ix-dot-netcom-dot-com
>To: tesla-at-poodle.pupman-dot-com
>Subject: Plasma coil?

>Just out of curiosity, has anyone ever considered making a secondary coil out 
>of gas filled glass, like a neon tube formed in the shape of a coil?  It seems 
>to me that an excited gas that produces a plasma may be a pretty good 
>conductor.  If nothing else, it might be good for a stage preformance.  
>Comments?

>Phil Gantt

>Phil Gantt (pgantt-at-ix-dot-netcom-dot-com)
>http://www-dot-netcom-dot-com/~pgantt/intro.html

Phil,

Interesting idea, but I see a potential problem with it (I love that 
pun!). 

When you first start the beastie there will be no plasma in the 
secondary tube, therefore there will be no 1/4 lambda tuned circuit 
there ready to develop the 'potential' necessary to ionize the entire 
length of gas in the tube.  At best I think you may only ionize the 
section of the tube that is in rather intimate contact with the 
powerful magnetic field of the primary near the bottom of the coil.  In order 
to get the ionization to grow the length of the secondary I believe 
you may have to feed the device with a variable frequency driver 
(which a traditional Tesla coil is definitely not), starting first at 
some higher frequency to light the bottom of the winding and then 
lowering the frequency in a downward sweep to increase the resonant 
wavelength of the gas, allowing it to grow in length as it chases the 
applied wavelength.

This is my hypothesis for a classical two coil design, on the other 
hand I believe that a magnifier where the bottom end of the 3rd coil, 
in this case our gas filled glass helix, is bottom end voltage fed, 
working with this applied RF voltage at the bottom and the big mass 
of the toroid at the top (counterpoise ground effect) I believe your 
tube would self start the entire length provided that the driver was 
powerful enough.  In this instance you are placing the entire helix in 
a voltage fed series circuit.  Once the entire helix was a plasma, it would be in 
tune and perhaps magnifier action would commence, although probably 
at such reduced efficiency due to effective secondary series 
resistance that you might not notice (probably too weak to breakaway 
the top terminal).

Just my thoughts.  Any 'neon' artists out there wanna prove me wrong?

Flames, bricks, Canadian money welcomed. : )

rwstephens