Composition of a non-self-sustained discharge plasma in an N2: O2: H2O mixture at atmospheric pressure

The plasma composition of a discharge sustained by a pulsed ionization source of μs duration is computed. It is shown that, within a time interval of ∼10⁻⁶ s after the ionization pulse, the dependences of the ion densities on the electric field and ionization source power show features that should be taken into account when developing laser systems for controlling electric discharges in long air gaps. The effect of the plasma composition on the efficiency of electron photodetachment from negative O ₂ ⁻ ions is investigated by the example of a discharge initiation system consisting of two lasers with different pulse durations and wavelengths. Plasmochemical processes under conditions of enhanced electron photodetachment from negative O ₂ ⁻ ions are simulated. It is shown that photodetachment can increase the electron density for a time of <10⁻⁵ s.