Physics of Rail Guns

The concept of rail gun is simple. Two parallel rods connected to the power supply generate an electric field. This electric field can be used to propel the projectile along the rod. If sufficient amperage is provided, the projectile may reach speeds of up to 4 km / s. For a long time, the US military was interested in the possibilities of electromagnetic guns. In 1988 the University of Texas Electromagnetics Center began researching a 9 MJ range gun designed to fire 2-4 kg projectile at a speed of up to 4 km / s.

Based on the same general principles as monopolar motors, railroad guns have been the focus of the military since the beginning of the 20th century. A simple track gun differs from a standard single pole motor in that it does not use an external magnetic field. A pair of conductive tracks connected to the power supply are connected by sliding armatures (or conductive projectiles) to complete the circuit. Current flows through one arm through the armature and back along another track. The current creates a magnetic field in the loop formed by the power supply, the rail and the armature. Like the unipolar motor diagram above, the magnetic field occurs perpendicular to the current plane and the armature plane and the orbital plane. Since the current and the magnetic field act in opposite directions along each trajectory, the resulting Lorentz force accelerates the armature along the trajectory. This acceleration can fire a projectile to hypersonic

There are two basic types of electromagnetic accelerators. A rail gun, commonly called a rail gun, consists of two rails with a rail projectile that slides between the rails to complete the loop. The current passing through the jet of the missile causes an acceleration force called Lorentz force. Although the rail gun is a very effective electromagnetic accelerator, its reliability is often low. In order for a rail gun to be effective, it requires several thousand volts, so a high current can overcome the resistance of the circuit. In the absence of a power supply capable of supplying extremely high voltage and current, "the frictional resistance is higher than the accelerating force and the projectile is welded to the orbit by resistive heating generated" (Baros). Asynchronous linear induction motor, another type of electromagnetic accelerator (commonly known as coil gun) works very differently from rail gun.