Ionization of molecular nitrogen by radiation from a channel surface discharge

Ionization of atmospheric-pressure nitrogen by nearly blackbody radiation from a channel surface discharge is investigated. By analyzing the data from measurements of the current of an electrostatic electron detector, the ionization rate of nitrogen and the time evolution of the electron density are determined. It is shown that the electron density reaches its maximum ～5 μs after the irradiation pulse. The results obtained indicate that the most probable mechanism for the observed nitrogen ionization is the formation of an ensemble of nitrogen molecules in metastable states and their subsequent collisional ionization, rather than direct one-photon or multiphoton ionization.