Investigation on the Characteristics of DC Air Discharge at Low Pressure Based on Hydrodynamics and Chemistry Model

Firstly, a presented model of hydrodynamics and chemistry which introduces an improved nonlocal collisionless electron heat flux and photoionization effect is used to simulate the low-pressure air discharge of DC. The plasma model is developed by COMSOL Multiphysics with plasma model and takes into account 12 species and 26 reactions which can accurately reflect the air discharge. Then, the characteristics and mechanism of air discharge under low pressure are analyzed. And this simulation model is validated by comparison between the experimental results and results in the current literature. The results show that N₂⁺ and O₂⁺ are the dominant positive ions; N₂ ionization reaction is always higher than O₂ ionization reaction; the cathode sheath has the greatest electron temperature due to the Joule heating in strong electric field; the main electron energy loss of volume in low-pressure air discharge is produced by inelastic collision.