Progress in 2n Megajoule Electrothermal Chemical Gun Pulser

Abstract

Pulse Power Components Branch ATTN: AMSRL-EP-MC Fort Monmouth, NJ 07703-5601 J. Creedon Consul tant Little Silver, NJSignificant progress has been made in both the laboratory and production versions of the 2N Megajoule Pulxr. The laboratory version has been operated at full voltage of 21 kV into a tens of milliohms load and the four pulse fornling networks comprising the pulser have been operated in excess of 800 microseconds apart. This phased operation enables precise control of the pulser in the megajoule range. Separation of pulses has produced complex cwrrent flows, which may be useful or detrimental. From a colmponent startdpoint, a significant achievement has been the successful application of simple, inexpensive solenoidal inductors, commonly used for utility line reactor applications, as pulse power components in the pulse forming networks. These iriductors can handle the peak current requirements of ETC gun pulsers, provided sufficient mechanical support is given to the component. The production version is nearing completion, and is ready to be installed in a semitrailer, for truly transportable operation. This is necessary, given the need for electrothermal chemical (ETC) guns to operate at remote ranges. 1ntroduc:tion The Army Research Laboratory (ARL) continues its program of research on the electrothermal chemical (ETC)gun. This is a chemical gun whose combustion processes are aided by pulse discharges into the chemical plasma, enhancing the operational efficiency of the gun. The Electronics and Power Sources Directorate of ARL is building a mobile, multimegajoule ETC gun pulser for the Weapons Technology Directorate of ARL, for use at the: latter's test range at Aberdeen Proving Ground, MD. The system consists of two 45 foot semitrailers, one housing the pulser, the olther a selfcontained 1 MW diesel generator power station, with charging power supply for the pulser. The pulser consists of a set of 2 MJ capacitor based pulse forming networks. Current plans call for two such units, down from an original three, for a total energy of 4 MJ. There is room in the trailer for two more such units, allowing for an expansion to a total energy of 8 MJ. The system is referred to as the 2N NU pulser, with N being the number of 2 MJ units. Details of the above have been previously reported [l-21.Activity during this past year has centered on two areas: experimental testing and final system design. Each are interrelated, in that the results of the ongoircg testing have great bearing on the final design alf the system. ExDerimentd TestingA key feature of this system is the division of the 2 MJ module into several submodules, each with its own switch and pulse shaping inductor. This is done in order to release the stored energy over a user variable time period, with each submodule's outpuo: combining as superimposing waves to form the desired pulse. This adds versatility to the system, yet increases the complexity d system control. Pulse widths are, relatively speaking, rather long, measured in milliseconds. This j...