Spatial distribution measurement of plasma palameters using spectral image processing

This paper presents an experimental method to determine qualitative two-dimensional images of gas temperature and mean electron energy in stationary atmospheric non-thermal plasma by using spectral image processing. In this work, steady-state glow corona discharge generated by positive DC voltage was observed. The electrode configuration was rod-to-plane and the ambient gas was synthetic air at atmospheric pressure. The changes of gas temperature distribution and mean electron energy distribution due to amplitude of applied voltage and ambient gas pressure were investigated. Spectral image of glow corona was taken by using a gated ICCD camera with ultra-narrow band-pass filters. The qualitative gas temperature and mean electron energy were derived from emission intensity ratios on obtained spectral images. As a result, we confirmed that the gas temperature and its distribution of positive DC glow corona increased with increasing the applied voltage. Especially, just before the spark-over voltage, a distinctly high-temperature region was formed in positive DC glow at the tip of rod electrode. On the other hand, the increase of mean electron energy at the tip of rod electrode was not as large as increase of applied voltage.