Spectroscopic study of positive streamer in short air gap

The technique developed for experimental investigations of basic physical parameters has been executed by Amin's metrological procedure modified for the spectroscopic time-resolved slit method. Relative and absolute luminosity intensities and shape parameters of waveforms of the second positive 2+(0, 0) and first negative 1-(0, 0) nitrogen bands have been measured in a DC cone-to-hemisphere (point-to-plane) positive streamer corona in short air gap at a distance 4 mm from the anode, under gap voltage of 10 kV, gap length of 1 cm, at NTP, with spatiotemporal resolution in the range between 0.7 and 2.0 ns. The following basic physical parameters in streamer head zone of primary streamer wave have been found: the electric field peak amplitude-100 kV/cm, the electron number density-(1-3)·1013 cm-3, the depth of on-axis electric field penetration into streamer body-0.2-0.25·mm, the length of an electric field damping along the outside boundary of the streamer head-1.0-1.5 mm, the radius-0.2-0.25 mm, and the front propagation velocity-2.5 107 cm/s. (4 pages)