Measurement Of Gas-Density Variation In Pulsed Streamer Discharge At Atmospheric Pressure By Mach-Zehnder Interferometry

In this study, gas-density variations occurring in pulsed streamer discharge at atmospheric pressure were quantitatively measured using a Mach-Zehnder interferometer. Experiments were performed using different gas compositions involving N-2 or air in humid or dry conditions. Spatiotemporal variations in the gas density after the discharge were characterised in terms of the energy relaxation process of the molecules. The measured gas-density variations were well reproduced by a zero-dimensional simulation model of vibrational-to-translational energy transfer in humid-air and humid-N-2 conditions. This indicated that the vibrational energy relaxation of N-2 through water molecules has a major effect on the gas density. However, the gas-density variations in dry-air and dry-N-2 conditions were not reproduced by the model; the corresponding etiology is outlined and discussed.