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
> 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!
> These electrons will immediately impact air atoms! (almost zippo mean free
> path) Oxygen, Nitrogen and Argon atoms are instantly ionized positively.
> These tremendously energetic electrons will literally rip electrons from the
> orbits of these atoms, and often not just one electron either! The result
> is a huge mass of secondary electrons which are themselves energetic, etc.
> This leaves the area about the immediate vicinity of the terminal loaded
> with ultra short lived high energy electrons.
> Also we have a large number of positive ions with much longer lifetimes ( up
> to 10,000 times longer lived) fleeing the area by impact and coulombic
> acceleration (repulsion). This explains the absolute absense of the
> negative charge anywhere outside of the Tesla coil's sparking circle.
> This also explains the failure of the tube and solid state coil to produce
> detectable charge elements at range. They are not true "gap" type switches
> and the system capacitors are not of the size and the voltages are not as
> high as in gapped systems. This means a real pip-squeak pulse of energy is
> present much more often from the output resonator, too. Thus, the average
> energy might be the same but the peak energy at any given time is always low
> and this much gentler action results in a willy nilly sort of mixed bag of
> plus and minus elements which are not energetic or coulombically
> accelerated. They recombine in the area immediately about the discharge.
> I have just finished a long and tedious read of an excellent reference text
> on this subject. It is old, but thorough, as are all older books. The Phds
> who wrote this old book supply the math but don't use it to the exclusion of
> countless hundreds of real world examples which are rarely presented in this
> day and age where math appears to be enough with no real solid examples.
> "Theory of Gaseous Conduction and Electronics" by Maxfield and Benedict, Mc
> Graw Hill, 1941
> Specifically, chapters 7-12. This is superb reference and I rate it up
> there with "Pulse Generators" in the MIT radiation laboratory series!
> Both of the above books are in my library now.
> 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 --