An actively switched pulsed induction accelerator

A coaxial accelerator which will launch a 45 mm diameter, 225 g-mass to 2000 m/s is described. The launcher is a true induction device, as no current feed to the armature is provided. The armature is a multiturn design, which forces a uniform current density and prevents excessive heating at the rear of the armature. To meet the 450 kJ launch goal, the accelerator is composed of 47 separate stages. Each stage has its own capacitor power supply, which is discharged on the arrival of the armature. The system uses a sense and switch approach to ensure correct timing of the power supply discharges. In-bore armature position is detected using fiber optics; the necessary signals are fed into a programmable controller, which determines the velocity. Using the calculation, the controller determines the ideal time to fire the next stage and initiates the discharge at the appointed time. The accelerator described is roughly 38% efficient (kinetic energy/stored energy) with a bore diameter of 45 mm. Simulations indicate efficiencies over 55% are possible with al 60 mm bore launcher and continue to increase with larger bore sizes. The launcher and armature designs, power supply, and controls are discussed. Predicted performance of a five-stage launcher currently being built is presented. Experimental results from single-stage tests are presented and compared to simulated results. Solid (monolithic) and multiturn (wound) armature tests are also described.<
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