Study of the characteristics of a streamer discharge in air based on a plasma chemical model

A detailed research on the streamer discharge local mechanism is necessary to enhance and develop the streamer theory. In the present paper, the characteristics of a streamer discharge in air at an atmospheric pressure are investigated using a hydrodynamic model based on plasma chemistry. Aside from continuity equations for electrons and ions, as well as Poisson´s equation for the electric field, the model includes the electron mean energy density equation and the neutral particle density continuity equation. The electric field strength and the velocities of streamer propagations obtained from proposed model are in good agreement with experimental and simulation results in literature. The mean electron energy is nearly constant in the streamer channel, except for a peak value at the streamer tip. Although the mole fraction of oxygen is only about 0.2 in air, oxygen ions are the dominant charged particles in the streamer discharge. At the electrode surface, the charged particle densities significantly decrease in the direction of the electrode because of surface reactions.