Study of dielectric barrier townsend discharge in air at atmospheric pressure

Summary form only given. As the most promising large-scale non-thermal plasma for industrial applications, dielectric barrier discharge (DBD) in atmospheric air usually behaves as filamentary discharge. However, it was found that diffuse DBD free of filaments could be produced in a 3mm air gap at one atmospheric pressure using two plane parallel electrodes each covered by one specific alumina plate bought from Zhuhai Yueke Co. LTD. Based on the discharge photographs of short exposure time taken with an ICCD camera, the discharge was identified with Townsend discharge. The Townsend breakdown voltage is only 5.7 k V, significantly lower than 11.2 kV, the static breakdown voltage of the 3mm air gap. If the alumina plates were replaced by 1mm-thick quartz plates which have the same capacitance with the alumina plates, it's impossible to get avoid filamentary discharges in atmospheric air or even the pressure went down to 1k Pa.