[TCML] Reflections on spark growth

[Peter Terren]

Streamer growth is interesting. I had always assumed that it happens on 
the basis of the (typical) 100kHz resonant frequency, rather than the 
1200Hz drive frequency of my fast ARSG or the 50Hz mains frequency.  My 
very old fast ARSG is here:
http://tesladownunder.com/tesla_coil_4inch.htm#Spark gap
My understanding of streamer growth is from my fast rotating mirror 
photos (streak camera) which show streamer growth at the 100kHz rate. My 
article is here:
http://tesladownunder.com/HVsparks.htm
The streak camera picture that shows each 200kHz (each direction of a 
single wave of 100kHz) until a strike is made is here. Vertical scale is 
thus moving at 5us per streamer. This is very fast.
Photos like this and others show streamer growth and then a strike on 
the microsecond time scale.
Yet I had also accepted D C Cox's technique of measuring spark length 
and voltage by running single shots with a DC coil (avoiding the mains 
50Hz or ARSG frequency).  This would only be relevant if 100kHz spark 
growth was not relevant.
So I am confused.
Is spark growth related to the 100kHz (F res) like my streak camera 
suggests? Or
Is spark growth related to the 8-10kHz (F res pri - Fres sec) like my 
streak camera suggests here?
          
http://tesladownunder.com/HVRotMirrorTeslaLargeStreamer3groups.jpg  Or
Is spark growth related to the spark gap frequency (SRSG of 100/120 Hz) 
or ARSG of up to my 1200Hz?
Is spark growth related to mains 50/60 Hz frequency?

Any thoughts?
Peter