A comparative study of three different types of barrier discharges in air at atmospheric pressure by cross-correlation spectroscopy

Microdischarges in a barrier discharge with an asymmetric electrode arrangement ('metal-dielectric') were investigated with fine temporal (down to 10 ps) and spatial (down to 10 mu m) resolution by the technique of cross-correlation spectroscopy. The discharge was operated in dry air at atmospheric pressure. The spatio-temporal distributions of the light intensities of the 0-0 transitions of the second positive (lambda = 337.1 nm) and first negative (lambda = 391.5 nm) systems of molecular nitrogen were compared with the corresponding experimental results for a symmetric electrode arrangement ('dielectric-dielectric') and for the coplanar barrier discharge. For all the discharge types being considered, the mechanism of electrical breakdown was found to consist of the Townsend pre-breakdown phase, the phase of ionizing wave propagation and the decay phase. Despite the qualitative similarity of the microdischarge development in different electrode arrangements, a detailed comparison of certain discharge characteristics (ionizing wave velocity, spatially or temporally integrated light intensity) enables us to reveal the influence of the electrode configurations on the process of electrical breakdown.