The study of negative needle-to-plane corona discharge with photoionization under various air pressures

The characteristics of negative corona discharge in practical applications are strongly dominated by environmental parameters, such as air pressure. An axisymmetric hydrodynamic drift-diffusion model considering the effect of air pressure and photoionization has been established in this study based on a traditional needle-to-plate configuration in dry air at room temperature. Trichel pulses, electron density, negative ion density, and electric field distribution during discharge are discussed to investigate the effect of air pressure and photoionization. The results show that the magnitude of the first Trichel pulse without photoionization decreases from 0.92 to 0.6 mA with the increase in the air pressure (0.7–1.1 atm). However, the magnitude of the third Trichel pulse without photoionization increases from 0.28 to 0.55 mA with the increase in the air pressure (0.7–0.9 atm), while it decreases from 0.55 to 0.47 mA with the increase in the air pressure (0.9–1.1 atm). Moreover, the decrease in the air pressure could result in faster movement of charged particles. The role of photoionization under different air pressures is also discussed by numerical simulations.