Re: TC Electrostatics (fwd)

To: tesla-at-pupman-dot-com
Subject: Re: TC Electrostatics (fwd)
From: Ed Harris <harris-at-parkave-dot-net>
Date: Mon, 7 Oct 1996 07:47:11 -0400
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> 
> >From what I *pretend* to understand ;) positive ions lack electrons, and
> negative ions have a surplus of electrons. In that case, in the first
> half-cycle, the positive ions would be accelerated farther away from the
> secondary's terminal than the following, heavier, and less-accelerated
> negative ions during their next half-cycle. This would be on the first
> completed cycle.

snip

> Of course, this is all just speculation, I'm no scientist. *laugh*
> But I do think that the ions will be accelerated to a point where the
> heavier negatives can't catch up. I'm also not sure about how to make the
> first cycle positive...maybe power-supply phasing? On the other hand, it
> could be that free electrons are being accelerated, since they're the
> lightest of all. I'd be way interested in finding out what the usual
> polarity-of-charge ends up being.
> 
> Just thinking out loud,
> 
> Dan
> 

Well, a point of contention:

even though negative ions have an extra electron, they essentially have the
same
mass as a positive ion of the same molecular species. The electron mass to 
nucleon (proton or neutron) mass ratio is about 1/2000 !!. So for an ions
like 
O2- and  O2+ each with 32 nucelons, the mass difference ratio is 
2/(32*2000)=1/32000 .

For discharges in air where O2 and N2 are both electron attaching gases,
you
most likely have an abundance of NEGATIVE ions with very few positive ions.
There will also be some "free" electrons with very high modility compared
to that of the ions. I would guess that negative ions are more prominant
near the
discharge so they would tend to repel each other and generate a negative
ion "wind" outward form the electrode.

BTW, long discharges in non-electron-attaching like argon or helium are
sustained
with much less power than in air (O2-N2) because the molecules in air
"suck-up" all the free electrons which are necessary for maintaining a
discharge
process. SF6 is even more electron-philic than O2 so dischages are even 
more difficult to maintain in that gas.

One way of getting to the bottom of this charging effect would be to
enclose your coil and collector electrode in and SF6 and an argon
environment
and compare the charing results.

-Ed Harris

>