Holy Cow! >100 meters?! That would be a site to see indeed! Bob V > As far as long free air sparks go, the Les Renardiers group in France > and the Soviets have both made very long air sparks (>100meters) with a > variety of impulse generators in the multi megavolt range. Once you get > above 3 or 4 MV, there really isn't any limit to the spark length, > assuming you have the stored energy to keep the spark propagating.