What is a railgun?

Although railguns sound like something from a science fiction movie, they are far from fictitious. Railguns are devices that can accelerate conductive objects using the electromagnetic Lorentz force. Unlike conventional gunpowder weapons, which are limited by gas expansion rates ect, railguns can accelerate objects to many times the speed of sound.

As shown in the picture above, the Lorentz force is created when a conductive projectile is placed between two conductive rails. One of the rails is connected to the positive terminal of a power source and the other is connected to the negative terminal. The current flows up one rail, through the projectile, and down the other. This creates magnetic forces that repel each other forcing the projectile forward at high speeds.

So if railguns are so good, why don't we use them in war?

Despite all of advantages of rail guns, they would be impractical for use in warfare. Railguns require huge amounts of energy fire a projectile at any significant speed. In order to provide these huge amounts of energy we would need an energy source too large and awkward to be carried around on a battlefield.

The enormous amount of electrical current flowing through the rails and projectile can also cause potential problems. The rails and projectile can become extremely hot due to electrical resistance, so hot that the rails and projectile can melt together welding the projectile in place.

As the projectile travels down the rails at high speed sometimes the it can lose contact with the rails and then come back into contact causing arcing and damage to the rails. Railguns suffer so much damage upon firing that a they would only be good for a few shots before they would have to be taken apart and repaired.

Railgun research by the U.S. military

The United states navy has been working on a railgun for military purposes. The experimental railgun is shown firing on the left. It can fire a projectiles at speeds up to 12 miles per second and as a range of over 100 miles!

The railgun is intended to be mounted on a war ship and used at long range. The power would be provided by the ships nuclear power plant. The high speed of the projectile means that it would be much more effective than today's gun powder weapons. The speed of the projectile is so great that it will partially vaporize its target

With railguns replacing modern explosive there would be no concern about unexploded bombs after battle. For example, in France, every once in a while you will hear about someone being killed by a leftover unexploded bomb for WWII. Since railguns use solid metal projectiles instead of explosive shells, this would no longer be a concern.

The navy's railgun research has come a long way since it started, but it still has a very long way to go. The main problem is that the rails are severely damaged by arcing with each shot and repair is very timely and expensive.