An electric arc is an electrical breakdown of a gas which produces an
ongoing plasma discharge, similar to the instant spark, resulting from a current
flowing through normally nonconductive media such as air. The various shapes of
electric arc are emergent properties of nonlinear patterns of current and
electric field. The arc occurs in the gas-filled space between two conductive
electrodes (often made of carbon) and it results in a very high temperature,
capable of melting or vaporizing virtually anything.
On a commercial basis, electric arcs are used for welding, for electrical
discharge machining, for movie theater projectors or street lamps (historic),
and to produce aluminum and sometimes steel using scrap. Calcium carbide is made
this way as well as it requires a strong endothermic reaction at 2500°C.
Low pressure electric arcs are used for lighting, e.g. fluorescent tubes,
mercury and sodium street lamps, camera flash lamps, plasma displays, and neon