Compact, megavolt, rep-rated Marx generators

A concept for compact, megavolt Marx generators has been developed, resulting in several designs which are approximately half the diameter and half the height of conventional units. The customized Marx capacitor assemblies utilize multiple windings incorporated into a single common capacitor case. Spark gap switch electrodes extend directly from the external capacitor terminals, eliminating the need for additional buswork. In order to construct the Marx generator, two capacitor assemblies are positioned opposite each other so that the electrodes line up in a vertical column between the two assemblies. Because the entire assembly is housed inside a pressurized (207 kPa of SF₆) gas vessel, the need for individual switch housings is eliminated. A four-stage, 400-kV-output Marx generator has been tested, operating at a repetition rate of 2-3 pps (power supply limited) continuously for over 5000 discharge cycles at 85-kV stage charging voltage. A second design has been fabricated and tested, utilizing 16 Marx stages to develop a 1.5-MV (open circuit) output voltage, and is contained in a cylindrical gas vessel 76.2 cm in diameter and 55.9 cm in height, weighing approximately 72.6 kg. Experimental measurements indicate a stage inductance of approximately 45 nH per 100-kV Marx stage