Time-resolved OES of nanosecond pulsed discharges in N$_{2}$ and N$_{2}$/H$_{2}$O mixtures]{Time-resolved optical emission spectroscopy of nanosecond pulsed discharges in atmospheric pressure N$_{2}$ and N$_{2}$/H$_{2}$O mixtures

TL;DR

This study investigates nanosecond pulsed discharges in nitrogen and nitrogen/water vapor mixtures at atmospheric pressure using time-resolved optical techniques, revealing distinct phases and emission characteristics during the discharge process.

Contribution

It provides detailed time-resolved optical emission data of nanosecond discharges in N$_{2}$ and N$_{2}$/H$_{2}$O mixtures, highlighting differences in emission phases and spectral features.

Findings

Discharges exhibit three phases: ignition, spark, and recombination.

Nitrogen emission dominates during ignition, atomic nitrogen during spark and recombination.

Adding H$_{2}$O introduces H$_{eta}$ emission and reduces N$_{2}$(C-B) intensity.

Abstract

In this contribution, nanosecond pulsed discharges in N$_{2}$ and N$_{2}$/0.9% H$_{2}$O at atmospheric pressure (at 300 K) are studied with time-resolved imaging, optical emission spectroscopy and Rayleigh scattering. A 170 ns high voltage pulse is applied across two pin-shaped electrodes at a frequency of 1 kHz. The discharge consists of three phases: an ignition phase, a spark phase and a recombination phase. During the ignition phase the emission is mainly caused by molecular nitrogen (N$_{2}$(C-B)). In the spark and recombination phase mainly atomic nitrogen emission is observed. The emission when H$_{2}$O is added is very similar, except the small contribution of H$_{\alpha}$ and the intensity of the molecular N$_{2}$(C-B) emission is less.