Re: Any Very High Freq. TCs?

To: tesla-at-pupman-dot-com
Subject: Re: Any Very High Freq. TCs?
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Thu, 03 Sep 1998 19:24:40 -0600
Approved: terryf-at-verinet-dot-com

to: Julian

Streamers terminate in thin air because the Tesla discharge is not at all a
classical discharge like 60 Hz or DC currents.  The Tesla RF discharge is a
"displacement current" which occurs in a capacitors dielectric -- in this
case air -- and the nature of these currents are very different than a
standard HV discharge.  For more information on displacement currents I
suggest you do some reading on Maxwell's work with displacement currents. 
The ARRL Radio Amateur's Handbook has a small section on displacement
currents as do most modern college level physics texts.  Unlike normal HV
discharges a displacement current does not need a grounded object to arc
to.

DR.RESONANCE-at-next-wave-dot-net


----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Any Very High Freq. TCs?
> Date: Thursday, September 03, 1998 6:31 AM
> 
> Original Poster: Julian Green <julian-at-kbss.bt.co.uk> 
> 
> > Original Poster: Steven Ivy <adder_black_the-at-yahoo-dot-com>
> > 
> snip...
> > volts at 1 GHz operating on my kitchen table : ) Is there some
> > particular flaw in this scaling idea other than the difficulty in
> > producing a spark gap capable of operating at these very high
> > frequencys.
> 
> Have you wondered why you get streamers that terminate in thin air?
> 
> Well I believe that it is due to the capacitance of the air
> and its ability to ionize forming conductive clouds of gas around
> the coil.
> 
> The current in a capacitor rises as the frequency increases.
> Therefore as the frequency of your tesla coil rises so does 
> the ability of the surrounding air to disipate the high voltage.
> 
> The result is that as frequency rises the streamers shorten. At
> about 1MHz you get discharges that look like a gas cooker flame
> and loads of ozone.  I think Richard Hull has photos if this.
> 
> If you want long and impressive streamers go for low frequency,
> around 100KHz.
> 
> How many turns on the secondary would you need for a 1GHz tesla
> coil?
> 
> Julian Green
> 
>