Spatiotemporal correlation between microdischarges in concentric ring pattern in dielectric barrier discharge at atmospheric pressure

The spatiotemporal correlation between microdischarges of the concentric ring pattern in a dielectric barrier discharge in argon at atmospheric pressure is studied by the wavelet-correlation technique for the first time. The concentric ring patterns lasting more than 5 min have been obtained under circular boundaries with different sizes by suddenly raising the applied voltage. The average correlation coefficient between microdischarge clusters increases with their discharge region increasing. The wavelet-correlation shows a higher correlation degree between the microdischarge clusters at the edge where $d|Uappl|dt<0$ than at the edge where $d|Uappl|dt>0$ in per half-cycle of the applied voltage $Uappl$⁠.