Plasma Armature Railgun Launcher Simulations at The University of Texas at Austin

A velocity-dependent friction model that accurately predicts the losses associated with a plasma armature railgun is presented. Test results from a 1-m-long, 1.27-cm square-bore, plasma-armature railgun have been used to determine the validity of the model. The divergence between the calculated and measured performance is typically less than 5% at railgun currents below 500 kA; however, at currents greater than 500 kA, the deviation increases. Experimental evidence suggests that the railgun's lack of stiffness and subsequent venting of driving pressure rather than the electromechanical model is primarily responsible for the divergence. To test this theory, a rail was built using external preloading rings (Ringfeder) to increase its stiffness. On the first test of the Ringfeder railgun, 625 kA was discharged into the gun and the projectile was accelerated to 5.9 km/s. Test data indicate that the projectile accelerated through the entire length of the railgun and that a minimum amount of plasma leakage occurred during the test