Original poster: Steve Conner <steve@xxxxxxxxxxxx>
When I ran my coil at 30 bps, it
caused this same "gas burner" effect of very short sparks all
around the toroid. The break rate was just too low.
The coalescence thing is interesting. I found that on my DRSSTC (Man's best
friend) I could get long sparks even at the lowest break rates. The best I
have done is a 22" strike to ground with a single 5 joule bang.
The sparks do look different at high break rates- they tend to bunch
together into a thick tree-like structure- but they really don't get that
much longer. The most I have ever seen from the coil is about 35" going
flat out with 200 5-joule bangs per second.
I think this is because the resonator is so small (13" overall height) and
the solenoid primary eats into the available space for E-field even
further. It just never develops enough of a field over a large volume of
space to grow long straight sparks. Adding power just causes strike rail
hits and flashovers.
With my spark gap coil I get the "Gas burner" effect and then the sparks
lengthen dramatically as the rotary gap motor is cranked up.