On electric field measurements based on intensity ratio of 1⁻ and 2⁺ systems of nitrogen in discharges with high specific deposited energy

Analysis of optical emission spectroscopy (OES) in application to the measurements of the electric field has been performed for the nanosecond capillary discharge in molecular nitrogen at moderate gas pressure at high specific energy deposition. Significant discrepancy between results of electric field measurements by OES technique and capacitive probe measurements is demonstrated. Decay rates of excited species as well as rotation structure of corresponding optical transitions are used to identify possible population/depopulation channels of the N 2 + ( B 2 Σ u + ) and N₂(C³Π_u ) states. Kinetic calculations taking into account additional quenching of the N 2 + ( B 2 Σ u + ) and N₂(C³Π_u ) states by electrons, additional population of N 2 + ( B 2 Σ u + ) by electron impact from the ground state of the molecular ion and by a reaction of excited N₂( A 3 Σ u + ) with the ground state of N 2 + describes adequately behavior of experimentally measured emission of both considered systems.