Simulation study on nitrogen vibrational kinetics in a single nanosecond pulse high voltage air discharge

Abstract

We report a simulation study on nitrogen vibrational kinetics N2(X1Σg+,v=0−12) in a single nanosecond pulse high voltage discharge in dry-air at a pressure of 100 Torr. Apart from the usual processes such as vibrational-vibrational exchange and vibrational-translational relaxation, the state-specific vibrational kinetics take into account the electronic-vibrational (E-V) process and chemical-vibrational process. The vibrational kinetics, coupled with electron Boltzmann equation solver, plasma chemical kinetics, and gas thermal balance are used to model the 100 ns discharge and its subsequent 10 ms afterglow. The self-consistent model shows good agreement with recent experimental results, with regard to time-resolved vibrational and translational temperature. According to the modeling results, The E-V mechanism has a small but non-negligible effect (about 2%) in rising of vibrational quanta in the early afterglow from 100 ns to 1μs. Another possible reason is the convective transport associated with the gas dynamic expansion in time delays around 1μs to 10 μs.

Vibrational CARS measurements in a near-atmospheric pressure plasma jet in nitrogen: I. Measurement procedure and results

“…This was not observed in [19] and [21], where no significant deviation from the populations predicted by V-V models was seen. More recently Yang et al [23] tried to explain the measurement results by numerical modeling but were also not able to reproduce the increase of the total number of vibrational quanta observed in the measurements. Consequently, the mechanism behind this process is still an open research question and will certainly vary for different discharge conditions and geometries.…”

Theoretical and experimental aspects of non-equilibrium plasmas in different regimes: fundamentals and selected applications

“…This model, determining at the same time the eedf and the thermodynamic state of the plasma, allows to consider variations in the plasma composition, electron-electron collisions and electron-induced processes from excited states of atoms and molecules. This approach has been applied to atomic systems [93][94][95], to molecular plasmas [96][97][98][99][100], also to evaluate the effects of using complete sets of vibrationally resolved cross sections [101,102], and to complex mixtures [103][104][105][106].…”

Vibrational CARS measurements in a near-atmospheric pressure plasma jet in nitrogen: I. Measurement procedure and results

“…This was not observed in [20] and [22] where no significant deviation from the populations predicted by V-V models was seen. More recently Yang et al [24] tried to explain the measurement results by numerical modelling but were also not able to reproduce the increase of the total number of vibrational quanta observed in the measurements. Consequently, the mechanism behind this process is still an open research question and will certainly be different for different discharge conditions and geometries.…”