Two-dimensional Measurement of N$_{2}$ Rotational Temperature Distribution in Atmospheric Positive DC Glow Discharge using Spectroscopic Imaging

An experimental method of determining a two-dimensional image of the N$_{2}$ rotational temperature in stationary atmospheric non-thermal plasma by spectroscopic imaging was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. Spectral images of a DC glow discharge were taken using a gated ICCD camera with ultra narrow band-pass filters, corresponding to the head and tail of a N$_{2}$ second positive system band (0-2). The qualitative N$_{2}$ rotational temperature was obtained from the emission intensity ratio between the head and tail of the N$_{2}$ second positive system band (0-2). The directions of observation were toward the lateral side and hemisphere sides of the rod electrode. The change in the distribution of rotational temperature in a positive DC glow discharge due to the amplitude of applied voltage was investigated. As a result, it was confirmed the rotational temperature and its distribution in a positive DC glow corona respectively increased and spread diffusely with increasing applied voltage. In particular, a distinctly high temperature region was formed in positive DC glow corona near the tip of the rod electrode just below the sparkover voltage.