Comparative study of homogenous dielectric barrier discharge in atmospheric inert gases

Summary form only given. Dielectric barrier discharge (DBD) at atmospheric pressure are easily to get homogenous in helium and neon, but always un-uniform in other inert gases. In order to have a deep understanding of the mechanism of DBD in inert gases at atmospheric pressure, Comparative study of the discharge mode, evolution of the homogenous DBD and spectra in a parallel gap were carried out by means of electrical measurements, fast photography and time-resolved emission spectroscopy in different inert gases. It was found that homogenous DBD could be easily produced in 2∼8mm gaps in helium and neon, and they were attributed to glow discharge. Compared to that in helium or neon, only a part of the 5mm-diameter electrode could be covered by homogenous DBD in 2mm argon gap. And a small increase of the applied voltage would convert the partly homogenous DBD into the pattern mode. If the gas gap was no less than 3 mm in argon, a bright filament would appear, and the current density could reach 7.5A/cm² in the steamer channel. High-speed time-resolved photographs of the homogenous DBD in helium, neon and argon were taken using an Intensified-CCD camera with an exposure time of 10ns. Side-view photographs showed an evolution from Townsend discharge to glow discharge. The end-view photographs showed a radial development. The spectroscopic diagnosis showed that penning ionization was very important to obtain a homogenous DBD. N2⁺ first negative system (B² Σu⁺ → X²Σg⁺) was observed in helium, but not observed in the neon and argon. The emission spectral lines of N2 second positive band system (C ³∏u → B ³∏g) could be observed in neon and argon.