Spatio-temporal dynamics and formation mechanism of the square super-lattice pattern with saturn-like white-eye in dielectric barrier discharge

We report a square superlattice pattern with two types of white-eyes in dielectric barrier discharge, one of which has an obvious black area around the center spot and is named "saturnlike white-eye." By using an intensified charge-coupled device, it is found that the pattern has five spatiotemporal sublattices, which should be the most complex pattern in dielectric barrier discharge to date. The results measured by the spectrograph and photomultiplier tubes show that the center spots of two types of white-eyes approximately have the same plasma parameters, while the current intensity of the center spot of saturnlike white-eye is about 1/3 of that of ordinary white-eye. Based on the above results, it can be estimated that the velocity of electrons in discharge of the center spot of saturnlike white-eye is much slower than that of ordinary white-eye, resulting in exhaustion of wall charges at the falling edge of voltage (d|U-app|/dt<0) and occurrence of discharge at the next rising edge of voltage (d|U-app|/dt>0). It inhibits discharge around the center spot and then the black area is formed. The differences of formation processes between two types of white-eyes are discussed. We believe that the research will contribute to advancement of pattern dynamics in dielectric barrier discharge. Published under license by AIP Publishing.