A study on the mechanism of ring-shape structure in the atmospheric pressure plasma jets

Summary form only given. Ring-shape is one of the feature characteristics of plasma bullet. However regarding the mechanism of the ring-shape structure of the plasma bullet, it is still not clear. In this paper, a series of special designed experiments are carried out to investigate the mechanism of the ring-shape structure of the plasma bullet. The typical ring-shape structure can be seen in Fig. l. In these experiments, the effect of the surface discharge and the effect of the surrounding gas diffusion are studied, thus the effect of Penning ionization can be separated. lt is found that both the diffusion of the surrounding air and the surface discharge play important roles in the forming of the ring-shape structure.