In order to analyze the spatiotemporal structure of the small-dot-line square superlattice pattern

the experiment of dielectric barrier discharge in air was carried out. The luminescence of small-dot-line square superlattice pattern was observed for the first time. Optical signals from the discharge filaments at different positions were measured by using photomultiplier. It is found that the luminescence of small-dot-line square superlattice pattern is an interleaving of three different transient sub-lattices. The discharge sequence is followed as the big-dot

small-dot

the line between two small-dots in each half voltage-cycle

and the small-dot and line are random. All of them occur at the rising edge of voltage. The instantaneous images show that the discharge time of big-dot mainly occurs in the front of the first current pulse

while the discharge time of small-dot and line is later than that of big-dot. The discharge position of small-dot and line between two small-dots are different in two successive half voltage cycles. The above results are consistent with the results of the optical signal. The electric quantities of the small-dot and line in two successive half voltage cycles are calculated. It is found that the polarities of wall charges are opposite and transferred charge quantities are equal

which has no effect on discharge of the next cycle. It is found that wall charges deposited on the dielectric surface have a great influence on discharge process.