Fig. 3

Simulation of dielectric barrier discharge (DBD) capillary plasma. a The transient voltage, electric field, electron density and electron temperature waveform with time at the points of tungsten electrode, capillary inner wall and ground electrode in one cycle, respectively. b, c Electron density and electron temperature profiles along the radius inside of capillary from tungsten to capillary inner wall at various typical time in one cycle. The value at the time of T/2 is highlighted by light yellow. d Time = T/2 (half of one cycle), electron density distribution in the cross section of the glass capillary with inner diameter of Ø1 mm and outer diameter of Ø1.54 mm. Diameter of tungsten wire electrode is Ø0.05 mm. Copper foil outside of capillary is grounded. The frequency f is 44 Hz. e Current waveforms of experiment, COMSOL model, and equivalent circuit model