RE: THOR Bang energy vs. streamer length measured

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

At 07:11 AM 7/28/2004 -0600, you wrote:
>Original poster: "Denicolai, Marco" <Marco.Denicolai-at-tellabs-dot-com>
>Hi Jim,
>
> > Increasing the break rate just raises the probability that
> > the long spark happens to occur where we're looking for it.
>
>Exactly.
>
> > However, what about the idea of sparks following previously
> > ionized/hot gas?  Perhaps this is a slower time scale, and
> > you'd see this effect in the under 100 bps range (probably
> > more down in the 10 bps)..  What's the time scale for
> > significant cooling of the spark channel?  Conductivity drops
> > real fast once you get below around 7000K, but that doesn't
> > mean that the breakdown voltage/ionization probabily along a
> > path isn't still higher than the surrounding areas.
>
>I agree with you: cooling of the channel is pretty slow. But that would
>affect the repeatibility of a discharge path, not its first formation.
>
>There is evidence (papers) proving that the deviation of the leader path
>is due to accumulated static charge in the gap. Sadly this has been
>always investigated for positive or negative discharges, never for
>alternate polarity (the TC case).


I was thinking that as a new spark starts to develop, it can more rapidly 
move through the previous channel, depositing the new charge as it 
goes.  Clearly, in a TC, with HV AC on the secondary, the charge has to 
flow back and forth through the spark channel during the "bang", but that's 
a fairly fast (i.e. speed of light) propagation, as opposed to leader 
growth, which is a 0.01c kind of thing.

I'm thinking of a faster time scale version of the dielectric treeing 
phenomenon, for instance.