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Re: Mini Coils and Streamer Quality
Subject: Re: Mini Coils and Streamer Quality
Date: Mon, 26 May 1997 10:02:26 -0800
From: Greg Leyh <lod-at-pacbell-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
References: 1
Malcolm Watts wrote:
[snip]
> Important point: this is direct evidence that streamer length
> depends heavily on power throughput. It was the same in both cases.
> Output voltages were quite different. The higher voltage/low BPS
> streamers had by far the greatest reach but never really formed what
> you would call an "arc". The top of the coil was surrounded by wispy
> showers of free-air streamers stretching out in all directions about
> 5" long. The drawn "arc" was shorter which showed power had to be
> concentrated in the arc to support it.
> With the 2kV/high BPS gap setting, the free air discharges were
> much shorter and fewer but now concentrated in bright flaming
> streamers we normally see at higher power levels. But the drawn arc
> was a fierce hissing plasma much longer than the free-air streamers,
> again about 3" long.
>
> This was fun! :) I am going to increase the supply capability
> to 100W (was around 40W) and try some more. The nice thing was seeing
> the full range of TC-type discharges in table-top miniature without
> wondering what was going to be struck next.
Congrats on the spark efficiency -- 40W/3" = 160Watts/foot !!
This is a useful data point on the spark length vs output power curve,
showing clearly that the relation is non-linear, favoring shorter arcs
and penalizing longer ones. I'm still trying to come up with a model
that could predict this curve, given that the current density in the
arc is constant, and the dissapated power per arc surface area is also
constant. Any more thoughts on this?
-GL