Electric discharge
A-D dark discharge
A-B: non-self-sustaining discharge and collection of spontaneously generated ions.
B-D: the Townsend region, where the cascade multiplication of carriers takes place.
D-I glow discharge
D-E: transition to a glow discharge, breakdown of the gas.
E-G: transition to a normal glow; in the regions around G, voltage is nearly constant for varying current.
G-I: represents abnormal glow, as current density rises
I-K arc discharge.
In electromagnetism, an electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (i.e., an outgoing flow of electric current through a non-metal medium).