Computational study of characteristics of atmospheric pressure glow discharge in helium

Numerical analysis of an atmospheric pressure glow discharge (APGD) in helium is carried out. Numerical models are spatially one- and two-dimensional and based on drift-diffusion theory of gas discharges. On the basis of the current-voltage and current density-voltage characteristic curves, the effects of the temperature regime on the cathode surface (cooled vs uncooled), the value of the secondary electron emission coefficient, and the thermal diffusion on the discharge parameters are studied. The possible transition of the discharge to an obstructed mode with gas heating is investigated. An analysis of the formation of normal APGD was carried out, which revealed good agreement with experimental data. The spontaneous emergence of cathode spots is illustrated and discussed.