Railgun Accelerators for Gram-Sized Projectiles

Abstract

In this paper, we describe the operation and critical parameters of railguns, we compare the potential and actual performance with other types of macroparticle accelerators, and we discuss their research and industrial applications. Railgun accelerators have the potential to accelerate massive projectiles to very high velocities in very short distances. Recent research has demonstrated the usefulness of railguns for research and industrial applications. The railgun accelerator is essentially a linear dc motor consisting of a pair of rigid parallel conductors that carry current to and from an interconnecting moveable conductor. The connecting link functions as an armature, and the parallel rails serve as a single-turn field winding. The resulting Lorentz force on the armature is proportional to the square of the current. A 1-MA current will produce about 2(105) N of thrust. A one-gram projectile will experience an acceleration of 2(108) m/s2 and in one meter achieve a velocity of 20 km/s. Conventional projectile launchers are limited to launch velocities of the order of 10 km/s. Hence railguns will enable research and applications at previously unattainable velocities. Velocities in excess of 10 km/s will lead to new research at high pressure and high-energy density. Behavior of matter in the 1-10 TPa or perhaps 100 TPa range will provide valuable insight to terrestrial and extraterrestrial phenomena. Furthermore, velocities of the order of 20 km/s will permit orbital launching from the earth's surface. These and other applications of railguns will be discussed.