Positive point-to-plane corona discharge forms in O2-N2 mixtures

An extensive survey has been made of positive point-to-plane corona discharges with 0–100% O₂ in O₂-N₂ mixtures in the pressure range 0.5–100 kPa. Selected results are presented in the form of pressure-voltage diagrams. They show the regions of existence for the different point-plane discharge forms observed: burst pulses, glow corona with oscillations, streamers, sparks, and a pulse- and oscillationless glow-spike corona. The latter positive corona discharge form has formerly only been observed in very pure nitrogen. The main aim of the paper is to give a short account of these different forms of positive coronas and their stability or oscillations, and to guide experimenters in establishing experimental conditions for future studies of these phenomena. Dedicated to Prof. Jan Janča on the occasion of his 60th birthday.