The effect of rail resistance on railgun efficiency

A time-dependent model of rail resistance based on one-dimensional current diffusion was developed and implemented in a railgun simulation code that can be used to study efficiency and losses in most railgun systems. Results were obtained for simple 500 kA, 2-m gun using metal armature. It is shown that typically 25% of the energy delivered to the gun is dissipated in rail resistance. The energy lost in the rails is about 75% of the final kinetic energy of the projectile. Gun efficiency can be improved by about 7% by simply cooling the rails to 77 K. Resistive voltage drop in the rails accounts for 33% of the breech voltage. Performance as measured by muzzle velocity depends on available power supply energy