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% O-2 in O-2-N-2 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.