Dielectric breakdown properties of N2–O2 mixtures by considering electron detachments from negative ions

The paper analyzes the dielectric breakdown properties of N2–O2 mixtures at different O2 concentrations and gas pressures, taking into account electron detachments from negative ions. The reduced effective ionization coefficients α(eff)/N in N2–O2 mixtures at different O2 concentrations and gas pressures were calculated and analyzed, by considering electron detachments. The critical reduced electric fields (E/N)cr and the critical electron temperature Tb were then determined. The result indicates a clear enhancement of α(eff)/N by collisional detachments, which causes a reduction in the (E/N)cr. In addition, a synergistic effect in the N2–O2 mixture was also observed in both (E/N)cr and Tb. The value of Tb was decreased by the increase of pd product, however, Tb tended to be constant at relatively high pd products.