Influence of gas temperature and gas species on the characteristics of low-temperature plasma

Low temperature plasma is expected to be applied to medical and agriculture fields. We developed multi-gas temperature-controllable plasma jet which can stably generate plasma of various gas species, and control the plasma gas temperature stably from 0 to 120°C. The developed plasma source has enabled us to irradiate plasma of appropriate gas species to heat-sensitive objects such as plants and skin. Using this plasma source, we have conducted studies on sterilization in liquids and introduction of proteins into plants. Those results are dependent on not only the gas species but the plasma gas temperature. The main factors for those plasma processes are considered to be reactive species such as \textbullet OH, $^{\mathrm{1}}$O$_{\mathrm{2}}$ and \textbullet O$_{\mathrm{2}}^{\mathrm{-}}$ Therefore, in this study, the influence of the plasma gas species and the plasma gas temperature on the generation of reactive species were investigated. For instance, when the O$_{\mathrm{3}}$ concentration in the O$_{\mathrm{2}}$ plasma whose gas temperature controlled from 0 to 80°C were measured, the concentration varied with the gas temperature, and the concentration showed the highest value at 50°C. In the presentation, the gas temperature dependence of H$_{\mathrm{2}}$O$_{\mathrm{2}}$, O$_{\mathrm{3}}$, \textbullet OH and $^{\mathrm{1}}$O$_{\mathrm{2}}$ generated by the plasma using Air, Ar, O$_{\mathrm{2}}$, CO$_{\mathrm{2}}$ and N$_{\mathrm{2}}$ will be shown.