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Re: A Puzzle




From: 	Richard Wayne Wall[SMTP:rwall-at-ix-dot-netcom-dot-com]
Sent: 	Thursday, September 04, 1997 1:50 PM
To: 	Tesla List
Subject: 	Re: A Puzzle

Bert wrote: 

snip

>> >The current levels required to support streamer growth are in the
>> >multi-ampere range.
>> 
>> snip
>> 
>> Bert, have these current levels been experimentally measured and
>> validated in the multi-ampere range?
>> 
>> RWW
>
>Richard,
>
>Yes. There's actually quite a large body of research that's been done 
>in the area of long-spark "arrested streamers" over the years. These
>experiments typically use a high voltage impulse generator (usually a
>triggered Marx Generator) connected to a rod-plane (non-uniform field)
>test gap. 

snip

So, actually all these "arrested streamer" experiments were *not* done 
with quarter wave air resonate coils?  And, the streamers and arcs 
looked like and were dead ringers for Tesla coil discharges?  So 
naturally it follows that experimentally measured discharge currents in 
nonresonate nonquarter wave systems extrapolate to Tesla coil discharge 
currents.  I would submit that these discharges probably resemble van 
deGraf generator sparks also.  Incidently, Van deGraf generators 
produce exceedingly low current discharges.  (Actually, TC discharges 
are much like Van deGraf discharges, ie., very low current.)  As we all 
understand, voltage in a tuned quarter wave resonator reaches its 
practical maximum and current approaches zero in the limit at the top 
termination.  

snip

>I happen to use a 25 watt tubular bulb, but a regular style light bulb 
>will also work as well. When the coil is running at full power, the 
>bulb is lit by the streamer currents forced to flow thru the bulb and 
>"into" the air. 
>
>By comparing the degree of brightness with an identical lamp driven 
>from a DC source, I found that this corresponds to about 110 mA of 
>"average" current. 

snip

Again, very subjective measurements.  The eye, as well as, the ear are 
nonlinear detectors.  Also, the intense electrostatic field at the TC 
termination causes ionization of gases and illumination in light bulbs.
This will introduce noncurrent error, particurally in a visual 
detection system.  

A much better method is to use a "current driven device" such as a LED. 
Dwayne Bylund has demonstrated very low curents associated at the top 
of a resonator coil with serial LEDs along the coil.  RH has an 
excellent video tape proving that LEDs have good frequency response in 
the range of most TCs.  An LED coupled to a fiber optic cable will 
detect TC current above its threshold.  The signal can be calibrated 
and compared to a known current value. 

RWW