Electron characteristics and dynamics in sub-millimetre pulsed atmospheric dielectric barrier discharge

Abstract The discharge characteristics and mechanism of sub-millimetre pulsed dielectric barrier discharge in atmospheric-pressure helium are investigated experimentally and theoretically, demonstrating that when the discharge gap distance is reduced from 1.00 mm to 0.20 mm, the discharge ignition time is reduced to approximately 40 ns and discharge intensity is enhanced in terms of the discharge optical emission intensity and density of the plasma species, (energetic electrons with energy above 8.40 eV). The simulated results show that as the discharge gap distance is further reduced to 0.10 mm, the number of energetic electrons decreases, which is attributable to the contraction of plasma bulk regime and reduction of electron density in the discharge bulk. Conversely, the proportion of energetic electrons to the total electrons in the discharge monotonically increases as the discharge gap distance is reduced from 1.00 mm to 0.10 mm. It is proposed that a gap distance of 0.12 mm is optimal to achieve a high concentration and proportion of energetic electrons in sub-millimetre pulsed atmosphere dielectric barrier discharge.