A plasma cannon (also called an electrothermal accelerator) is an experimental
projectile weapon
A ranged weapon is any weapon that can engage targets beyond hand-to-hand distance, i.e. at distances greater than the physical reach of the user holding the weapon itself. The act of using such a weapon is also known as shooting. It is someti ...
, which accelerates a projectile by means of a
plasma discharge between
electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials d ...
s at the rear of the barrel, generating a rapid increase in pressure. It functions similarly to other types of
firearms, except that it uses a plasma discharge instead of a
chemical propellant
A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...
(e.g.
black powder or
nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
).
Design
To generate the energy required to make a plasma discharge, a high current,
high voltage
High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant sp ...
source, and a large
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
bank are used. Both are attached in series to the electrode system in the cannon's barrel. The capacitor is loaded with as high a voltage as possible. However, militarily useful energy is achieved with as little as several
kilojoule
The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applied ...
s. The capacitor is then discharged. The gap between the electrodes
ionize
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...
s, turning the
non-flammable
A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
propellant medium into a
super heated conductive
plasma. Associated volumetric expansion propels the projectile from the barrel at high velocity.
Advantages and disadvantages
The advantage of a plasma cannon is that it uses electricity as its energy source. The more energy that is supplied the faster the gases expand and the faster the projectile can be accelerated. This makes it possible to "dial-in" any velocity desired and allows the projectile to reach a speed at which it would be possible to "outrun" the burn rate of a conventional propellant.
A clear disadvantage of the plasma cannon is its weight. Even a small plasma cannon with only the firepower of an
air gun weighs about 20 kg (without current supply). A foot soldier thus could not carry a plasma cannon powerful enough to be useful. It would have to be mounted in a stationary position or on a vehicle. It would be impossible for a soldier to carry a plasma cannon with the firepower of an actual cannon.
See also
*
Electrothermal-chemical technology Electrothermal-chemical (ETC) technology is an attempt to increase accuracy and muzzle energy of future tank, artillery, and close-in weapon system guns by improving the predictability and rate of expansion of propellants inside the barrel.
An elec ...
Further reading
*Günter Wahl: ''Blitz und Donner selbst erzeugt'' (in German)
Artillery
Plasma physics
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