[Investigation of plasma parameters of the square pattern with two kinds of spatiotemporal symmetry in dielectric barrier discharge].

Two kinds of square patterns with different spatiotemporal symmetry were observed in dielectric barrier discharge, and their plasma parameters were measured by using optical emission spectra. It was found that the spatiotemporal symmetry of the square pattern at lower gas pressure is different from the one at higher gas pressure. Six spectral lines in the emission spectrum of the N2 second positive band were chosen to estimate the vibrational temperature, and the ratio of I391.4/I394.1 was used to represent the average electron energy. The excitation temperature was determined by the ratio of I763.2/I772.1. Furthermore, the width and shift of Ar I 696.54 nm were used to estimate the electron density. The results show that the vibrational temperature, excitation temperature and electron energy of the square pattern at lower gas pressure are higher than those at higher gas pressure, while the electron density is lower than that at higher gas pressure.