Highly resolved observation of the primary wave emission in atmospheric positive-streamer corona

The emission of repetitive streamer corona was observed by a photon counting method with a high time resolution. The half-width of the main pulse of the primary wave corresponding to the emission from the 0.014 mm length part in the direction of the electrode axis is found to be only 0.8 ns. This primary wave emission has the nature of transient developing glow discharge which has the cathode glow, cathode dark space and negative glow. The faint but steady build-up of emission which continues from the cathode toward the cathode glow, suggests a considerable secondary electron emission from the cathode during the period of the primary wave propagation.