Spectroscopic study of a positive streamer in a point-to-plane discharge in air: evaluation of the electric field distribution

A spectroscopic diagnostic of the streamer point-to-plane discharge based on the spectrum emitted by the excited molecules and ions of N 2 was used to obtain the spatial electronic temperature distribution in the streamer head. The assumption of a Townsend electrical equilibrium allows the spatial distribution of the local and space-charge fields to be obtained. The electronic temperature presents a maximum of about 9 eV at a distance 2 mm from the point electrode, while the value of the reduced electric field at the same position is about 280 V cm -1 Torr -1 . The evaluated distribution of the electric field and the geometric field distribution were used to obtain the space-charge field distribution.