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RE: Lightning vs. Tesla Coil Discharges

The cloud as a capacitor:

Each cloud stands alone as a capacitor, 
in addition to its lower boundary portion forming yet another capacitor to
earth ground.

Inside the cloud, the humidity is very low (its real cold so won't hold
liquid moisture).
Clouds are filled with circulating particles of frozen ice which serve to
transport charge.
Result is a great charge polarity difference between the top and bottom of
the cloud, 
representing virtual capacitor plates (high charge density emulates a
conductor plate).
The action is not unlike a Van de Graf charge transport on a giant scale. 
Most lightning occurs within & between (proximity) clouds.

However the charge accumulating on the lower boundary relative to its
distance to ground
results often enough in ground strikes as we've all witnessed.

Recommended reading:  National Geographic, July, 1993 - nice picts too.
This describes detail and pictorials of inner cloud action. 

image was here but appears to have moved :( 
(one of the best picts ever made of lightning strike)
http://www.meitca-dot-com/HSL/People/steve/lightnin.html

Regards, Dale
Redondo Beach, Calif.



-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, November 10, 1999 10:49 AM
To: tesla-at-pupman-dot-com
Subject: Re: Lightning vs. Tesla Coil Discharges


Original Poster: Bryan St <warp27-at-juno-dot-com> 



On Mon, 08 Nov 1999 06:20:17 -0700 Tesla List <tesla-at-pupman-dot-com> writes:
> Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 
> 
> Hi All,
> 
> While reading Jim Lux´s answer to my post on filming
> TC arcs, a few questions popped into my head:
> 
> While coils can be (and ARE) very impressive, I´m sure
> all will agree lightning is the hands down winner, when it
> comes to the *really* impressive discharges.
> 
> What is a cloud in the sense of source? Is it *just* an
> ultra high voltage source or is it a high current source? I
> would guess the latter, because the plasma channels
> lightning creates can easily be several inches (maybe
> even feet) in width. This discharge channel gets so hot
> that we can hear the air being displaced (the thunder).
> Wouldn´t a Marx generator be a more *exact* equivalent
> of man-made lightning?

I think I read somewhere that lightning is somewhere in the 10^9 order of
magnitude.  I definetely agree with this.

> 
> What capacitance (roughly of course) does a cloud have?

That isn't difficult to calculate.  We all know the dielectric constant
of air is one, so if anybody knows average cloud height and area we have
our answer.

<snip>
> 
> >Current keeps flowing because once the channel is
> >formed, it's resistance drops dramatically (that
> >negative V/I curve).
> 
> This might well be the reason why a TC will almost always
> perform better with a larger toroid. The more Ctop, the
> more current (and not voltage) our TC can deliver to the
> arc channel. Maybe it is also the reason, why low voltage
> (high current) powered coils don´t perform worse than
> hv coils do ;o)).

I believe that this is also a function of more efficient energy transfer
with higher current but I am not a HV engineer.  Does the v/i curve mean
that higher capacitance (to a point of course)will give you higher
voltage output because you can maintain the spark as its voltage drops in
a marx generator?

<snip>
> 
> >Once the channel has reached 7000K, the conductivity
> >is so high that the IR heating drops off.. Essentially, the
> >entire leader is "regulated" by a sort of negative feedback
> >(heat loss proportional to T^4, heat input proportional to
> >I^2R, which is inversely proportional to temperature) to a
> >temperature just high enough to keep it "well ionized". So
> >the point where two leaders meet is probably no hotter
> >than anywhere else along the leader.
> 
> This brings another thought to mind. What would happen
> if we could (in some way) make a discharge path which
> is surrounded by a gigantic magnetic field? This should
> keep the plasma bundled and very hot. What would happen
> if we constructed this magnetic field similar to a coil gun? In
> other words using not one, but several magnetic coils along
> the discharge path. Could one accelerate or even stretch
> the actual coil discharge?

I don't think so because magnetic fields make electrons spiral(this is
why an uwave has such fat magnets) which increases breakdown voltage. 
Alas, I am no HV engineer and I could not tell u for sure.
> 
<snip>
> 
> 
> Coiler greets from Germany,
> Reinhard
> 
> 
> 
> 
> 
Bryan
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