Toroid breakout power requirements

I wonder if anyone has ever attempted to determine the amount of power 
required to cause a given size toroid to discharge in an arc. The way I 
see it, a toroid has a physical shape which limits the amount of voltage 
which it can withstand before a breakdown in air. Since the voltage is, I 
believe, directly related to the charge on the toroid and the charge is 
limited by the power available, then doesn't it follow that there is some 
minimum power required to cause a specific sized toroid to discharge?
This all assumes, of course, that some standard set of conditions prevail 
such as humidity, temperature, etc. Several recent posts have alluded to 
a relationship between the geometry of the sphere, oblate, toroid, or 
whatever and the maximum voltage it will stand off. 

I would appreciate any information which anyone has relating to this 
subject. One obvious result of a real relationalship would be the 
possibility of designing a specific coil to match the power xformer to 
the toroid and thereby achieve a maximized coil xformer combination..

Skip Greiner