Re: streamer

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

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

This is very interesting... I've been reading up on the whole spark growth
thing.

Something that is somewhat unique to TC's  (as opposed to long gap sparks,
as used in impulse testing, or lightning) is that they make lots of sparks
into "space".

It seems that sparks grow with two mechanisms.. a bunch of "streamer"s which
move very fast (>10% light speed) and are basically an ionization wave, and
not very luminous. They move fast, then die out, so their life is very very
short (would that I had the camera with nanosecond exposure times that they
use to see these things)  These all emerge from the "head" of a leader, and
there's not much charge or energy in them, and their voltage drop is fairly
high.  The leader is the visible spark you see, and carries the current to
provide the charge and energy to create the streamers.  This current causes
heating of the leader which makes its resistance low, and makes it hot
enough to glow, and see.  The leader is very conductive, and as such, it has
significant capacitance.

The interesting thing about TC's is that they can support a leader for a
long time without it connecting to the other electrode.  A typical "long air
spark" has this brush of streamers being created as the leader moves out,
and finally the leader gets to the other electrode, and a signficant current
flows to neutralize all the charge in the leader making a classical "arc" to
keep the spark alive (as long as there is energy in the source).  In a TC,
the leader never gets to the other electrode, so this can't be the way  way
to keep the current flowing.  But, in a TC, the polarity of the electrode is
reversing on every half cycle, so charge is continuously flowing in and out
of the leader, raising its current, and keeping it hot.

Very interesting stuff...

I suspect that if you were to set up several cameras at different angles,
with fast shutter speeds and sensitive film, and trigger them
simultaneously, you could get some very interesting data.  With cameras at
an angle from each other, you can (using photogrammetry) actually figure out
the 3D path of the spark(s).
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, March 10, 2001 12:01 PM
Subject: streamer


> Original poster: "Metlicka Marc by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <mystuffs-at-orwell-dot-net>
>
> all,
> i was looking through some digital pics of my 3000k coil running last
> fall when i found this, the only capture of a streamer, my girlfriend
> snapped at the right time. i lightened it up and found that it shows an
> interesting event, it was at a point where one streamer was failing and
> another was just forming in another spot of the topload?
> i think it is very interesting that though the leader is breaking out at
> a bright point on the toroid, the energized area is more of an ion cloud
> around it?
> thought some might find it interesting, wish i had the camera set at max
> res.?
> marc m.
>
> http://hot-streamer-dot-com/temp/DCP00544a.jpg
>
>
>