Coilgun

A coilgun or Gauss rifle is a type of projectile accelerator consisting of one or more coils used as electromagnets in the configuration of a linear motor that accelerate a ferromagnetic or conducting projectile to high velocity. In almost all coilgun configurations, the coils and the gun barrel are arranged on a common axis. It is not a rifle as the barrel is not rifled. The name 'Gauss' is in reference to Carl Friedrich Gauss, who formulated mathematical descriptions of the magnetic effect used by magnetic accelerator cannons. A coilgun or Gauss rifle is a type of projectile accelerator consisting of one or more coils used as electromagnets in the configuration of a linear motor that accelerate a ferromagnetic or conducting projectile to high velocity. In almost all coilgun configurations, the coils and the gun barrel are arranged on a common axis. It is not a rifle as the barrel is not rifled. The name 'Gauss' is in reference to Carl Friedrich Gauss, who formulated mathematical descriptions of the magnetic effect used by magnetic accelerator cannons. Coilguns generally consist of one or more coils arranged along a barrel, so the path of the accelerating projectile lies along the central axis of the coils. The coils are switched on and off in a precisely timed sequence, causing the projectile to be accelerated quickly along the barrel via magnetic forces. Coilguns are distinct from railguns, as the direction of acceleration in a railgun is at right angles to the central axis of the current loop formed by the conducting rails. In addition, railguns usually require the use of sliding contacts to pass a large current through the projectile or sabot but coilguns do not necessarily require sliding contacts. While some simple coilgun concepts can use ferromagnetic projectiles or even permanent magnet projectiles, most designs for high velocities actually incorporate a coupled coil as part of the projectile. Another form of Gauss rifle is one which consists of a strong magnet on a rail. There are two metal balls on one end of the magnet. Another ball is placed next to the magnet, but not attracted to it. When the ball is pushed toward the magnet, it accelerates until it hits the magnet with some force and velocity. The momentum is transferred through the magnet to the last ball, which flies off the end with nearly as much force as the first ball started with. The first operational coilgun was developed and patented by Norwegian scientist Kristian Birkeland in 1904. In 1933, Texan inventor Virgil Rigsby developed a stationary coilgun that was designed to be used like a machine gun. It was powered by a large electrical motor and generator. It appeared in many contemporary science publications, but never piqued the interest of any armed forces.