Study on the Self-Organized Pattern in an Atmospheric Pressure Dielectric Barrier Discharge Plasma Jet

In this paper, a rich variety of self-organized patterns have been observed in a dielectric barrier discharge helium plasma jet generated at atmospheric pressure. It has been found that the evolvement of a discharge pattern in plasma jets is sensitive to diverse experimental parameters, including the applied voltage, the frequency of power, the scale of plasma jet generator, and the gas flow rate. By altering the applied voltage and/or the gas flow rate, the plasma jet is seen to evolve through three modes, which are diffuse-looking discharge, self-organized discharge with regular channels, and unstable discharge with random filaments. Among which, the self-organized discharge mode is characterized with several bright plasma channels stably formed in a straight line. The maximum number of channels is mainly determined by the scale of plasma jet generator. When the frequency is fixed, the minimum distance between two adjacent discharge channels in the self-organized mode is nearly the same, no matter what size tube is selected.