Electron-vibration energy exchange models in nitrogen-containing plasma flows

TL;DR

This paper investigates vibrational energy exchange in nitrogen plasma due to electron collisions, analyzing relaxation dynamics and providing models and fits for vibrational relaxation times across a wide temperature range.

Contribution

It introduces new cross sections and rate coefficients for vibrational excitation, and develops analytical models for vibrational relaxation times in nitrogen plasma.

Findings

Vibrational relaxation times are characterized across 0-50000 K.

Reduced models for vibrational kinetics are validated.

An analytical fit for relaxation time is provided.

Abstract

The physics of vibrational kinetics in nitrogen-containing plasma produced by collisions with electrons is studied on the basis of recently derived cross sections and rate coefficients for the resonant vibrational-excitation by electron-impact. The temporal relaxation of the vibrational energy and of the vibrational distribution function is analyzed in a state-to-state approach. The electron and vibrational temperature are varied in the range of [0,50000] K. Conclusions are drawn with respect to the derivation of reduced models and to the accuracy of a relaxation time formalism. A analytical fit of the vibrational relaxation time is given.