Railguns

Abstract

Electric guns, theoretical and practical, have been around for many years in many forms. They have been slow to develop however because the competition, in the form of gas dynamic guns, has been formidable. To accelerate solid projectiles to interesting velocities by electrical means requires large amounts of conveniently available electrical energy. This more than anything has inhibited their development. The completion of the large homopolar generator in Canberra changed that. It was used to power a railgun which propelled three-gram projectiles to 5.9 km/s. In the past few years other railguns have been built, two of which have produced high velocities, using both explosively driven magnetic flux compressors, and electrostatic capacitors. Two more installations will launch much larger masses. Enough is known now to design realistic railguns and rail gun systems. It is known for example, the conditions under which solid armatures can be expected to work and when plasma armatures are required. Railguns are now being designed for a range of applications varying from the 'scientific' with velocities of more than 20 km/s with projectile masses of a few grams, through many military applications, to railgun systems capable of launching many tons ballistically from the earth's surface into space.