A 6.6 MJ modulator for electrothermal chemical guns

The authors discuss a versatile 6.6 MJ modulator that is designed to be used in studies of electrothermal chemical (ET/C) guns. The modulator can provide megajoules of pulse energy of varying durations into significantly different impedances with efficiencies of 70% or greater. The system is housed in two trailers. The first contains a 1 MW diesel generator, a DC power supply, and a local control system. The other contains the capacitor banks, inductors, switches, and buswork. Coaxial cables connect the modulator to the gun some 10-15 m away. The system can be taken into the field where no power is locally available. The electrical design of the modulator is a C-type pulse forming network utilizing time-variable triggering of the various sections. The flexibility in the triggering system permits the modulator to provide a wide range of pulse shapes into significantly different loads. Computer-simulated output curves are presented showing operation into loads typical of ET/C guns, as well as indicating a range of possible impedances and pulse shapes