Effective Discharge Area of Nonequilibrium DC Discharges

Intensified charge-coupled device images are used to determine an effective discharge area in low-pressure DC discharges. We show radial emission profiles for all typical regimes of low-pressure discharge - dark Townsend discharge, constricted normal glow, and abnormal glow discharge. These data are used to obtain current densities in a wide range of conditions, which is essential for a proper scaling of discharge parameters.