sparks running down secondary - why?

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

Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vanyo-at-echoes-dot-net>

Last time I ran my coil, I got occasional loud snappy sparks running
down the length of the secondary, as well as occasional firing of my
safety gap.  Wondering what causes the sparks down the secondary, and if
it's a problem?

The only change I made since my previous run (which was still
underperforming, but perhaps due to wind - not sure - this is my first
coil) was to hook my NST power supply (three 15/60's, two with internal
PFC) to a seperate 20 amp line.  I could now run it without tripping the
breaker.  I still plan on hooking it to a 30 amp 240 volt line, stepped
down by variac to 120 volt.

Oh, and the other change is a bigger topload.  Originally, I had a
smaller toroid, and now have added a larger one on top.  I can run with
just the larger.

	Thanks again,
	Bill V. 

Specs again:

Power Supply: Three 15/60 NST's (two have internal PFC), with Terry's
protection filter on the
high voltage side, and redundant line filters and a 50 amp variac on the
120V side.

Capacitor: A Maxwell 30 kV, 0.06 uF cap (model # 37321).

Static Spark Gap:  9 copper pipes mounted in a blower box, with
adjustable spacing.

Secondary: 1000 turns of 22 awg, 6.5" (closer to 6 5/8) diameter, 27.5"
winding length.  Countless coats of polyurethane.

Primary (just rebuilt): Flat spiral, 10 turns of 1/4" copper tube, 1/2"
spacing on centers.  Inside diameter 9.5".  Tapped between 6 and 7
turns.

Toroid: I have two toroids, both aluminum dryer duct, and constructed
so  I can easily attach either or both.  The smaller is 6 inch cord with
14 inch center to center spacing, and the larger is 8 inch cord with 24
inch center to center spacing.

Ground: 32" segment of copper clad iron ground rod.