what determines if breakout will occur?

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

Original poster: "Laurence Davis by way of Terry Fritz <twftesla-at-qwest-dot-net>" <meknar-at-hotmail-dot-com>

is it merely a factor of the toroid size compared to top terminal voltage?  
as in you have a toroid of x dia, y cord thickness and for it
to breakout the voltage needs to be Z (ok bad choice of arbitrary var.)
does frequency effect breakout voltage? as in AIR has RF dissipation factor 
and higher frequencies would require higher voltages for breakout.  streamer 
thickness is a factor of the amount "over" the breakout voltage, as in 
current or power available?

therefore to determine breakout voltage would be a function of
dv/dt of cap(topload) - dv/dt of secondary output? ignoring frequency.
since topload has the ability to retain potential for a period of time
T.

okay, i'll run on even more if i don't quit now.
simple question: if you have a toroid/sphere of some size, if breakout 
occurs, does that mean that a specific voltage has been reached?
for example: a 6 six sphere will breakout at above 80kv.  so if you have a 
breakout using said sphere, your output voltage is at least 80kv.
correct?  even though surrounding surfaces and EM field affect breakout 
(right?) would that still be a close enough approximation?

larry d.