Coilgun

A coilgun is a type of projectile accelerator that consists of one or more coils used as electromagnets in the configuration of a synchronous linear motor which accelerate a magnetic projectile to high velocity. The name Gauss gun is sometimes used for such devices in reference to Carl Friedrich Gauss, who formulated mathematical descriptions of the magnetic effect used by magnetic accelerators.

Coilguns consist of one or more coils arranged along a barrel. The coils are switched on and off in sequence, causing the projectile to be accelerated quickly along the barrel via magnetic forces. Coilguns are distinct from railguns, which pass a large current through the projectile or sabot via sliding contacts. Coilguns and railguns also operate on different principles. The first operational coilgun was developed and patented by Norwegian physicist Kristian Birkeland.

In 1934 an American inventor developed a machine gun similar in concept to the coilgun. Except for a photo in a few publications, very little is known about it.