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Re: Explanation of the positive E.S. charge
At 11:16 PM 1/28/97 -0700, you wrote:
>> Subject: Explanation of the positive E.S. charge
>
>Subscriber: bert.hickman-at-aquila-dot-com Tue Jan 28 23:10:45 1997
>Date: Tue, 28 Jan 1997 21:11:09 -0800
>From: Bert Hickman <bert.hickman-at-aquila-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Explanation of the positive E.S. charge
>
>Tesla List wrote:
>>
>> Subscriber: rhull-at-richmond.infi-dot-net Mon Jan 27 22:15:37 1997
>> Date: Mon, 27 Jan 1997 11:08:46 -0500 (EST)
>> From: richard hull <rhull-at-richmond.infi-dot-net>
>> To: tesla-at-pupman-dot-com
>> Subject: Explanation of the positive E.S. charge
>>
>> All,
>>
>> A while back we were musing over where the positive charge comes from in gap
>> operated Tesla coil. Well, thanks to a bit of digging, now that issue is
>> settled, I think. If we let a DC or AC high voltage leak slowly and quietly
>> into the air as mild corona (as in an ionizer), we are emitting electrons
>> and thus negative charge. I have measured this negative charge around two
>> ionizers which I have with my Keithley electrometer.
>>
>> With the tesla coil we are pulsing near megawatt level blasts of peak energy
>> into the output resonator. (Even in small table top models!) With the take
>> off rod I use in the E.S. experiments, especially one with high work
>> functions and needle points, we are ripping and accelerating very high
>> energy electrons from the metal's surface in a field which is often 10s of
>> megavolts per meter. This is field emmision with a vengance, in air!
>>
big snip
>> Richard Hull, TCBOR
>
>Richard and all,
>
>The explanation certainly sounds plausible. [BTW, I also have the
>Maxfield and Benedict Book - you're certainly right - it IS a keeper!].
>Assuming the above explanation is correct, do you have any further
>thoughts on what's behind the difference in polarity when using the
>electrostatic voltmeter versus the electrometer, or why the polarity
>seemed to drift and change during some of the experiments? In the latter
>case, could the measuring ball have been near the region where the
>positive and negative charges were roughly in the same proportion, and
>for the most part tended to cancel each other out?
>
>BTW, is the "Pulse Generators" book the one by Glasoe and Lebacqz, or
>another one? I'm still trying to locate a copy of this excellent book!!
>
>Safe coilin' to you, Richard!
>
>-- Bert --
>
>Bert,
Once charging the ball collects only positive charge at any range!
Naturally, this is outside the sparking circle. I have place the collector
as close as 4" from the tips of the farthest sparks. ( a dangerous thing to
do with the $5000.00 Keithley) The charge is always positive.
The voltage reading remains a concundrum It is always negative. Often at 8
feet from the 30 watt coil the voltage slams to minus 200 volts (limit of
the Keithley in a fraction of a second while the coulombmeter reading takes
a few seconds to climb to 10^-7 coulombs of collected positive charge on the
12 pf sphere. I feel the latter may be related to the manner in which the
meter functions which I will seek to understand next, now that I feel I know
the absolute charge polarity.
I show all this in great detail on tape #55 where I verify the charge
polarity with a charged 18th century electroscope! It agrees with the Keithley.
Pulse Generators is the one by the authors you mention. It is the fifth
volume in the RAD LAB series of 1948.
By the way, I joined the ESA- Electrostatics Society of America last year
(an organization of professionals and scientists involved with the actual
application and study of E.S. phenomena). They offer a rare lecture tape
produced by prof. Melcher of MIT, entitled, "Electric fields and moving
media" which is one of the most interesting and incredible tapes I have even
seen. It was lifted from a 16mm film produced for classroom use. It
details a lot of little known phenomena associated with liquids and gases
and their interaction with E.S. fields.
Thanks for the continuing interest.
Richard Hull, TCBOR
>