Development of a modular electromagnetic launcher system for the air force armament laboratory

An electromagnetic launcher (EML) system was developed for the Air Force Armament Laboratory (AFATL) to use in studying all aspects of rail accelerators. The EML accelerates 10 g arc-driven projectiles to velocities >3 km/s. It employs 4 m rails, has a 10 mm circular bore, and is driven by a low-impedance pulse-forming network (PFN) capable of delivering 250 kJ with a peak current of 450 kA and pulse length of 1.8 ms. Key design features include (1) preacceleration to minimize arc erosion of rails, (2) a projectile fuse that ignites the arc and eliminates external switching, and (3) careful matching of EML and PFN impedances at the current peak to maximize energy transfer to the arc. The EML's helium-driven preaccelerator propels the projectile to 500 m/s before it enters the rail accelerator. Power comes from five PFN modules charged to 800 V. Values of network elements are easily adjusted to change pulse characteristics for exploring a wide range of EML parameters. AFATL has written an EML modeling code that simulates all power source configurations. The EML system and code will be used to improve efficiency and reliability and to optimize components of a potential EML weapon.