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Re: Phantom Arcs



Grayson Dietrich wrote:

> wierd, very long, extremely dim, white arcs
> 
> A long time ago, when I first began experiementing with Tesla coils, I
> noticed something unusual from one of my experiements. Strange, dim,
> very profuse, thick, white arcs visible only in the dark that gave no
> sensation when touched.
>...
> When the gap was set so there were
> only a few breakdowns per second, hot, snappy sparks ~1.5" could be
> drawn from the 1.25" steel ball terminal, while a thick,  tree-shaped
> swath of the pale white "phantom" streamers could be drawn with no
> sensation to my outstretched hand as far away as 7". If I removed my
> hand, only a few short, thin examples of the phantom arcs would remain
> visible, and no other dischrges were apparent.

These "phantom" streamers are easy to observe in electrostatic
machines. They are probably spark "leaders" too long and difuse to heat
the air enough for a true spark. Something as a wave of electrons
moving from a negative area to a positive area, without forming a
complete ionized channel. One step ahead of simple corona.
Measurements that I have made show that these "failed" sparks
do not discharge completely the terminals.
With low break rate in a Tesla coil, you have essentially the same 
kind of sparks seen in an electrostatic machine.
That long unconnected streamers that appear when the break rate
is high are probably caused by repeated sparks of this kind in the 
same incomplete channels, since then there is no time between breaks 
for the complete deionization of the air, that heat enough some of the
channels to form a clearly visible three of unconnected sparks.

Antonio Carlos M. de Queiroz