Re: arc brilliance

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

Original poster: "Stephen Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>

At 12:17 31/03/03 -0700, you wrote:
>Original poster: "Rikard Titus by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <rikard_titus-at-hotmail-dot-com>
>
>
>Hi ,
>Tesla Coil arcs often appear more illuminated at their ends where they 
>attach to struck objects.

I read ACMQ's explanations as to why arcs can be brighter/dimmer at one 
end, but I noticed that arcs to ground from my OLTC mini coil sometimes 
show a bright spot in the middle. It seems to be located at the point where 
the streamer from the breakout point and the streamer from the ground point 
met. Can anyone explain this? You can just about make it out in this 
picture (8 second time exposure) The coil is running at very low power and 
producing about 2 bangs per second.

http://www.scopeboy-dot-com/tesla/singlebang.jpg

In this pic (running at about 600bps) it appears near the right-hand end of 
the one or two streamers that did connect. This is more like what the 
original poster described. The extreme bright spot visible at the ground 
electrode was probably corona rather than any property of the arc as such.

http://www.scopeboy-dot-com/tesla/oltcstrikes.jpg

The OLTC is a great tool for research because of its repeatability and 
controllability.

Steve C.