Editing Electric current (section)

===Gases and plasmas===
In air and other ordinary [[gas]]es below the breakdown field, the dominant source of electrical conduction is via relatively few mobile ions produced by radioactive gases, ultraviolet light, or cosmic rays. Since the electrical conductivity is low, gases are [[dielectric]]s or [[Electrical insulation|insulators]]. However, once the applied [[electric field]] approaches the [[dielectric breakdown|breakdown]] value, free electrons become sufficiently accelerated by the electric field to create additional free electrons by colliding, and [[ionizing]], neutral gas atoms or molecules in a process called [[avalanche breakdown]]. The breakdown process forms a [[Plasma (physics)|plasma]] that contains enough mobile electrons and positive ions to make it an electrical conductor. In the process, it forms a light emitting conductive path, such as a [[Electrostatic discharge|spark]], [[electric arc|arc]] or [[lightning]].

[[Plasma (physics)|Plasma]] is the state of matter where some of the electrons in a gas are stripped or "ionized" from their [[molecule]]s or atoms. A plasma can be formed by high [[temperature]], or by application of a high electric or alternating magnetic field as noted above. Due to their lower mass, the electrons in a plasma accelerate more quickly in response to an electric field than the heavier positive ions, and hence carry the bulk of the current. The free ions recombine to create new chemical compounds (for example, breaking atmospheric oxygen into single oxygen [O<sub>2</sub> → 2O], which then recombine creating [[ozone]] [O<sub>3</sub>]).<ref>{{cite web | title = Lab Note #106 ''Environmental Impact of Arc Suppression'' | publisher = Arc Suppression Technologies | date = April 2011 | url = http://www.arcsuppressiontechnologies.com/arc-suppression-facts/lab-app-notes/ | access-date = March 15, 2012}}</ref>