Two different arrangements were used. The single-filament DBD was ignited in a Plexiglas cell with quartz windows. It holds two hemispherical alumina-covered electrodes with 2 mm radius featuring a 1 mm gas gap and 0.5 mm dielectric thickness at the tips.

The multi-filament arrangement with was positioned in a pumpable stainless steel chamber with a quartz window at the front, gas inlet on the top, gas outlet at the bottom. To exclude any impact of the dielectric material on the comparison between the single- and the multi-filament DBDs, the same alumina tubes (manufacturer Friatec) were used for both arrangements. The multi-filament arrangement with 1 mm gas gap consists of two parallel alumina cylinders with 4 mm outer and 2 mm inner diameter with metal rods of 2 mm diameter inside. The thickness of the dielectric in the gap d_b is 1 mm on each electrode. The lateral length of the 1 mm gas gap is about 10 mm with an increasing gas gap distance at the left and right end due to the hemispherically-shaped tips.