Dependence of negative ion formation on inhomogeneous electric field strength in atmospheric pressure negative corona discharge

摘要

The dependence of negative ion formation on the inhomogeneous electric field strength in atmospheric pressure negative corona discharge with point-to-plane electrodes has been described. The distribution of negative ions HO-, NOx- and COx- and their abundances on the plane electrode was obtained with a mass spectrometer. The ion distribution on the plane was divided into two regions, the center region on the needle axis and peripheral region occurring the dominant NOx- and COx- ions and HO- ion, respectively. The calculated electricfield strength in inhomogeneous electric field established on the needle tip surface suggested that the abundant formation of NOx- and COx- ions and HO- ion is attributed to the high field strength at the tip apex region over 10(8) Vm(-1) and the low field strength at the tip peripheral region of the order of 10(7) Vm(-1), respectively. The formation of HO-, NOx- and COx- has been discussed from the standpoint of negative ion evolution based on the thermochemical reaction and the kinetic energy of electron emitted from the needle tip.