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A '''Railgun''' is a type of artillery that fires projectiles at supersonic speeds by launching them using [[electromagnetism]] instead of gunpowder or  some other chemical propellant. Current expectations for railguns are a 400-mile (643.6 kilometer) range and an impact velocity in excess of [[Mach]] 8.  

A '''Railgun''' is a type of [[artillery]] that fires projectiles at [[supersonic]] speeds by launching them using [[electromagnetism]] instead of gunpowder or  some other chemical propellant. Current expectations for railguns are a 400-mile (643.6 kilometer) range and an impact velocity in excess of [[Mach]] 8.  

==Design==

==Design==

Railguns are specifically weapons that consist of two conductive rails (often made of [[copper]]) and a conductive projectile which is inserted between the rails.  A current is passed up through the negative rail, across the projectile and then down the positive rail, completing the circuit at the power supply. In some cases, the projectile itself is the sole conductor, while in other cases, a sabot us used to carry the (usually non-conductive) main projectile.  Alternatively, a plasma armature can be used--in this setup, thin metal foil is wrapped around a non-conductive projectile.  When power is run through the rails and foil, the foil vaporizes into plasma, which caries the needed current. The flow of electricity causes the railgun to behave like an electromagnet, and the [[Lorentz force]] causes the projectile to be launched down the rail.  This process is specific to the functioning of the railgun, thereby giving the weapon its name.<ref>[http://www.technologyreview.com/Infotech/20164/?nlid=857 Technology Review, Feb. 2008: "Electromagnetic Railgun Blasts Off"]</ref><ref name="HSW rail1">http://science.howstuffworks.com/rail-gun1.htm</ref>

Railguns are specifically weapons that consist of two conductive rails (often made of [[copper]]) and a conductive projectile which is inserted between the rails.  A current is passed up through the negative rail, across the projectile and then down the positive rail, completing the circuit at the power supply. In some cases, the projectile itself is the sole conductor, while in other cases, a sabot us used to carry the (usually non-conductive) main projectile.  Alternatively, a plasma armature can be used--in this setup, thin metal foil is wrapped around a non-conductive projectile.  When power is run through the rails and foil, the foil vaporizes into [[plasma]], which caries the needed current. The flow of electricity causes the railgun to behave like an electromagnet, and the [[Lorentz force]] causes the projectile to be launched down the rail.  This process is specific to the functioning of the railgun, thereby giving the weapon its name.<ref>[http://www.technologyreview.com/Infotech/20164/?nlid=857 Technology Review, Feb. 2008: "Electromagnetic Railgun Blasts Off"]</ref><ref name="HSW rail1">http://science.howstuffworks.com/rail-gun1.htm</ref>

The power requirements of a rail gun are enormous.  Significant power generation capability must be connected to [[capacitor]]s so that the needed jolt of energy can be released. For larger rail guns, such as the military hopes to use, millions of amps are required to produce a sufficient electromagnetic force.<ref name="HSW rail1">http://science.howstuffworks.com/rail-gun1.htm</ref><br />

The power requirements of a rail gun are enormous.  Significant power generation capability must be connected to [[capacitor]]s so that the needed burst of energy can be released. For larger rail guns, such as the military hopes to use, millions of amps are required to produce a sufficient electromagnetic force.<ref name="HSW rail1">http://science.howstuffworks.com/rail-gun1.htm</ref><br />

The Railgun should not be confused with the coilgun, also known as the Gauss gun, a weapon which works by generating an electromagnetic field using coils external to the barrel, and using a projectile that is contactless with the firing mechanism (the coils).

The Railgun should not be confused with the coilgun, also known as the Gauss gun, a weapon which works by generating an electromagnetic field using coils external to the barrel, and using a projectile that is contactless with the firing mechanism (the coils).

==Purpose==

==Purpose==

[[Image:Railgun Navy1.jpg|right|thumb|250px|Photograph taken from a high-speed video camera during a record-setting firing of an electromagnetic railgun (EMRG) at Naval Surface Warfare Center, Dahlgren, Va., on January 31, 2008, firing at 10.64MJ (megajoules) with a muzzle velocity of 2520 meters per second.  At this speed, the test projectile actually burns, causing the wave of fire behind it.]]

[[Image:Railgun Navy1.jpg|right|thumb|250px|Photograph taken from a high-speed video camera during a record-setting firing of an electromagnetic railgun (EMRG) at Naval Surface Warfare Center, Dahlgren, Va., on January 31, 2008, firing at 10.64MJ (megajoules) with a muzzle velocity of 2520 meters per second.  At this speed, the test projectile actually burns, causing the wave of fire behind it.]]

Railguns provide a capability for sustained, offensive power projection, complementary to missiles and tactical aircraft. They may be a cost-effective solution to the Marine Corp Naval Surface Fire Support requirements because of their unique capability to simultaneously satisfy three key war-fighting objectives:

Railguns can provide the capability for sustained, offensive power projection, complementary to missiles and tactical aircraft. They may be a cost-effective solution to the Marine Corp Naval Surface Fire Support requirements because of their unique capability to simultaneously satisfy three key war-fighting objectives:

#Extremely long ranges

#Extremely long ranges