Measurements of Rotational Temperature and Density of Molecular Nitrogen in Spark-Plug Assisted Atmospheric-Pressure Microwave Discharges by Rotational Raman Scattering

概要

論文の詳細を見る
Rotational Raman scattering was adopted for measuring the spatiotemporal evolutions of the rotational temperature ($T_{\text{r}}$) and the density ($n_{\text{N2}}$) of molecular nitrogen at the electronic ground state in spark-plug assisted atmospheric-pressure microwave discharge. The rotational temperature had a spatial distribution with the peak at the plasma center. The temporal evolution of $T_{\text{r}}$ suggests a long confinement time of heat in this plasma source. Because of the long confinement time of heat, the plasma was in a nonequilibrium state for at least ${\sim}1$ ms after the initiation of the discharge. We observed the depletion of $n_{\text{N2}}$ as well as the decrease in the partial pressure of N<sub>2</sub> ($P_{\text{N2}}$). They were more significant at a longer distance from the plasma center. The depletion of $n_{\text{N2}}$ at the plasma center was roughly explained by the increase in $T_{\text{r}}$. On the other hand, we have speculated that the significant decreases in $n_{\text{N2}}$ and $P_{\text{N2}}$ in the peripheral region of the plasma is owing to dissociation of N<sub>2</sub> followed by nitriding of solid surfaces.
2011-07-25