Analysis of plasma arcs in arc-driven rail guns

In this paper we present a relatively simple model for estimating the properties of the arc in arc-driven rail guns. The model assumes that the arc is steady in a reference frame that accelerates with the arc/projectile system, and accounts for the effect of finite rail height on the accelerating force and on the arc properties. The model is used to investigate the effect of arc mass, projectile mass, and accelerating current on arc properties. The results indicate that the arc pressure is a function primarily of the accelerating current, whereas the arc length and arc temperature depend on both the arc mass and the current. Except for the acceleration, arc properties are generally insensitive to the mass of the projectile for projectile masses much greater than the arc mass.