Influence of asymmetric degree on the characteristics of a homogeneous barrier discharge excited by an asymmetric sine

Abstract

An atmospheric pressure dielectric barrier discharge driven by an asymmetric sinusoidal voltage has been investigated numerically with a one-dimensional fluid model. Results indicate that, as a controlling parameter, the asymmetric degree (Das) of applied voltage can significantly affect discharge characteristics. With an increasing absolute value of Das [abs(Das)], the maximal current density remains almost constant at low abs(Das) and increases significantly at high abs(Das), while the phase of the discharge with the maximal current gradually approaches toward 0° of the applied voltage. Meanwhile, discharge transits from a Townsend mode to a glow mode. Moreover, the electron density (ne) increases more than three orders of magnitude during this process, hence it is viable to manipulate ne by adjusting Das. Besides, N4+ is the predominant positively charged species with abs(Das) lower than about 60%. Out of this range, He2+ takes the place of N4+, becoming the predominant positively charged species. Further investigations reveal that in the primary discharge, direct ionization takes an important role with high abs(Das), while Penning ionization becomes important with low abs(Das). Moreover, dominant reactions for electron production are clarified. These results are of great significance in the manipulation of ne for a homogeneous barrier discharge.