Mechanism of the Influence of Field Emission on Corona Discharge at Microscale

Based on the electric field enhancement effect of one-dimensional nanomaterials, field-ionized micro-corona devices can generate atmospheric pressure non-equilibrium micro-plasma, which is suitable for gas detection and biomedical fields with fast response and low power consumption. However, the corona discharge at the microscale is a local self-sustaining low-energy discharge, and the role and influence mechanism of its field emission are still unclear. Therefore, in this paper, based on the fluid-chemical mixing model, the F-N emission model is introduced and coupled to establish a two-dimensional microcorona discharge model for the N₂-O₂ gas mixture at room temperature and pressure. By comparing with the discharge model without field emission, the effect of field emission on the dynamic process of discharge under different spacing is explored. It is found that when the pin-plate spacing is reduced to 15 μm, the difference in the discharge process between the two models is very small, indicating that the discharge is dominated by the secondary electron emission mechanism, and when the spacing is reduced to 10 μm, the difference in the discharge intensity between the two models is nearly a factor of one, and the role and influence of field emission cannot be neglected; And through further dynamic analysis of electron density distribution, space electric field distribution, current density and other parameters, it is found that there is a chain influence law between field-induced emission, space collision ionization reaction and ion bombardment secondary electron emission.