Effect of Driving AC Voltage Frequency on Breakdown Voltage in Dielectric Barrier Discharge at Atmospheric Pressure in Helium

For dielectric barrier discharge(DBD)driven by AC voltage in helium at atmospheric,the relationship between the breakdown voltage and the driving frequency is experimentally investigated using a pair of parallel electrodes.The gap between the electrodes is 1 mm,4 mm,7 mm,and 10 mm,respectively.Meanwhile with an increment of 2 kHz,the applied AC voltage varies from 12 kHz to 30 kHz.In each experiment,the driving voltage increases slowly,till the helium-filled gap breaks down.Based on a number of experimental results and further analyses,conclusions are obtained as follows.(1)For a small gap(1 mm),the voltage that triggers the first breakdown(Uf)is close to the one that sustains steady breakdowns(Us).However,in the larger gaps(4,7,and 10 mm),Uf is obviously larger than Us.(2)For a fixed gap,Uf does not change significantly with the driving frequency,whereas in the gaps except the 1 mm one,Us drastically decreases with the increase of driving frequency.(3)The motion of residual space charges and the dissipation of positive column,two reasonable factors that explains asymmetrical discharges,are also main reasons for the effect of the driving frequency on the breakdown voltages.

For dielectric barrier discharge （DBD） driven by AC voltage in helium at atmospheric, the relationship between the breakdown voltage and the driving frequency is experimentally investigated using a pair of parallel electrodes. The gap between the electrodes is 1 mm, 4 mm, 7 mm, and 10 nun, respectively. Meanwhile with an increment of 2 kHz, the applied AC voltage varies from 12 kHz to 30 kHz. In each experiment, the driving voltage increases slowly, till the helium-filled gap breaks down. Based on a number of experimental results and further analyses, conclusions are obtained as follows. （1） For a small gap （1 mm）, the voltage that triggers the first breakdown （Uf） is close to the one that sustains steady breakdowns （Us）. However, in the larger gaps （4, 7, and 10 ram）, Uf is obviously larger than Us. （2） For a fixed gap, Uf does not change significantly with the driving frequency, whereas in the gaps except the 1 mm one, Us drastically decreases with the increase of driving fi＇equency. （3） The motion of residual space charges and the dissipation of positive column, two reasonable factors that explains asymmetrical discharges, are also main reasons for the effect of the driving frequency on the breakdown voltages.