Spatiotemporal characteristics of nanosecond pulsed discharge in an extremely asymmetric electric field at atmospheric pressure

In this paper, high resolution temporal-spatial diagnostics are employed to research the optical characteristics of nanosecond pulsed dielectric barrier discharge in needle-plate electrode configuration. Temporal-spatial distributions of discharge images, the emission intensities of optical emission spectra, and plasma vibrational and rotational temperatures are investigated. By analyzing the evolution of vibrational and rotational temperatures in space and time dimensions, the energy distribution and energy transfer process in plasma are also discussed. It is found that a diffuse structure with high density plasma concentrated in the region near the needle tip can be presented in nanosecond pulsed discharge, and an obvious energy transfer from electronic energy to vibration energy can be observed in each discharge pulse.