Air is a dielectric. Not a great one, but a sufficient air gap between two electrodes prevents arcing. (I may not be expressing this the best way, but you all know what I mean.) If you lower the air pressure greatly, would a high voltage spark leap across the same distance? I imagine something like a charged flash capacitor being lofted in a balloon. The poles of the cap are connected to electrodes separated by a gap sufficient to prevent discharge at normal air pressure. If the balloon lifts the apparatus to, say, 100,000 feet, will we see the apparatus arc over when the air is sufficiently attenuated? Or will we get a kind of corona glow? Or nothing?
A camera would be pointed at the gap to film the result. Paul Thompson _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla