Re: Electrum waveforms, was: Then what's the topload FOR?

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Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


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From: "Tesla list" <tesla-at-pupman-dot-com>
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Sent: Tuesday, February 19, 2002 8:09 PM
Subject: re: Electrum waveforms, was: Then what's the topload FOR?


> Original poster: "Peter Lawrence by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
>
> Bert,
>      is it believed that the 7 HF oscilations in the 2-us/division
B-waveform
> represent streamer "leaders" forming, that the ?-foot arc produced at the
> time this oscillograph was taken was formed in 7 increments.
>
> Do people think that "leaders" form at a constant length, and that for a
> smaller TC there would only be one leader jump, and that for larger TCs
> generating larger sparks that there could be multiple leader jumps. OR
> is there some reason why leader jumps would be shorter in a small TC and
that
> their sparks would also grow in several smaller jumps.

At least for lightning, the leader jumps appear to be of relatively constant
length.  I think the same is true of long air sparks at lower energies (
lightning is ca. 100 kJ/meter), and I would imagine that the length of jump
is tied to things like spark channel diameter (which determines R, L, and C
of the spark channel).  One theoretical description has it following sort of
this sequence...

Charge accumulates in channel and at end of channel, increasing field at end
until breakdown voltage is reached, then
leader starts propagating, charge flowing out of the channel into the new
chunk of leader, until
charge is depleted in the channel, or series resistance rises, or step
function propagates, or, or... and leader growth stops,
charge flows into channel.....repeat

>
> >
>
> This is why I think that a streak photo of a TC spark formation,
especially
> if it could be coordinated with the oscillographs of the type they took of
> Electrum, would be very enlightening to us TC builders/enthusiasts.

Streak cameras, and high speed framing cameras, are a construction challenge
that is pretty complex (they make a RSG seem trivial by comparison.. spin a
mirror at 10,000 RPM +, fast electrooptical shutters (Kerr cells, using
truly vile and dangerous chemicals), lots of optical alignment.  There are
some million frame/second cameras around, but they aren't cheap to
rent/use...  But, if someone happened to have access to one, etc...
>
> -Peter Lawrence.
>
>