Performance characteristics of a 1 MV miniature Marx bank

In this paper, the authors report results of experiments with a compact Marx bank generator. The Marx was constructed with 25 spark-gap switched stages, each stage consisting of two Murata 2nF capacitors with N4700 ceramic dielectric rated at 40 kV. In order to evaluate the Marx efficiency and repetition rate, inductive isolation with 5 /spl mu/H per stage was implemented for the charging circuit. The Marx was charged with a 1500 J/s capacitor charging power supply. The system was controlled and monitored with a laptop computer through a fiber optic interface. The authors report results from operating the Marx from one quarter to full output voltage, nominal 250 kV to 1 MV open circuit (OC). Short duration testing showed that the Marx could be triggered continuously at a repetition rate varying from 20 to 50 Hz, depending on the charging voltage. Various representative loads were used for diagnostic purposes and for comparison to modeling efforts. When operated into a short circuit, the Marx current oscillated at 14 MHz with a peak amplitude of about 10 kA. The Marx was also operated with and without a coaxial ground enclosure to investigate the influence of this geometry on pulse characteristics. They compare the results of circuit modeling with the experimental measurements and show good agreement.