Emission Characteristics of Surface Microdischarge in Atmospheric-Pressure He/N2 Mixture

The surface microdischarge in atmosphericpressure He/N₂ mixture is studied with an emphasis on its emission characteristics. It is found that the emission intensity and the pattern shape are strongly dependent on the N₂ concentration. The UV emission intensity increases by a factor of nine with the N₂ concentration up to 5%, after that it decreases moderately. Meanwhile, the luminous pattern expands and then shrinks from grounded mesh edge to the mesh center in the positive half-cycle, while it gradually brightens and then darkens in the central region of a mesh for the negative half-cycle, which is mainly attributed to the distribution of surface charge. In the case of [N₂] = 2%-5%, the UV-Vis emission intensity is stronger and the emission pattern is comparable to spatial homogenous, thus benefiting the light emission applications.