Electric Cartridge Guns Using Fluids Heated by a Capillary Plasma Jet - An Extension of Classical Gun Technology to High Velocities

The contractor is developing a gun technology in which electrically driven cartridges are used to fire projectiles at hypervelocities using conventional design reusable gun barrels. The cartridge device makes use of a high impedance capillary plasma jet situated inside the cartridge or breech block. This enables electrical energy to be efficiently injected into a relatively cool low atomic weight propelling fluid. The cartridge can be driven by various power supplies such as a capacitive pulse forming network, homopolar inductor system, or compulsator. Pulse shaping of the delivered power can be designed to maintain a nearly constant pressure projectile acceleration compatible with the barrel strength. Further, since the propelling fluid can start out in the projectile acceleration cycle at liquid densities, kilobar pressures can be achieved with low fluid temperatures at early times when the projectile dwells near the barrel entrance. The fluid temperature is then increased with time as higher sound speed is needed to maintain pressure on the projectile base during it acceleration along the barrel, thereby minimizing barrel ablation as required for rapid fire guns. Finally we note the since the cartridge has a high impedance of typically approx. 0.1 ohms relatively low currents only a few hundred thousand suffice to couple the required power levels into the gun. Thus, low mass transmission lines can be used to convey this power to the gun from power supplies located at a convenient distance.