Electron heating mechanism in radio-frequency microhollow cathode discharge in nitrogen

A two-dimensional particle-in-cell/Monte-Carlo code has been developed to study the electron heating mechanism in radio-frequency microhollow cathode discharge (rf-MHCD) operated in nitrogen at 100 Torr. The influence of secondary electron emission coefficient (γ) on the electron density and total ionization rate, the occurrence of α ionization rate and γ ionization rate, and the electron heating rate are calculated. The results show that compared with the condition of γ = 0, the maximum electron density at γ = 0.1 shows an increase of 60% and the maximum total ionization rate increases by nearly one order of magnitude, which indicates secondary electron heating in rf-MHCD plays an important role. Through the detailed distribution of γ ionization rate and α ionization rate by two-electron model, it is found that γ ionization rate is about 90% of the total ionization rate and the spatial distribution of γ ionization rate presents the same characteristics of the total ionization rate. Therefore, we can furt...