Characterization of plasma in RF jet interacting with water: Thomson scattering versus Spectral line broadening *

This work reports on comparison of plasma characteristics measured by means of Thomson scattering and spectral line analysis. Both measurements were performed on RF powered plasma jet, running at 20% duty cycle, with Ar as a carrier gas. The plasma was impinging on a water surface located 1 cm away from the powered needle electrode. To support the plasma analysis, we also have performed gas temperature measurement by means of laser Rayleigh scattering and detailed time-resolved imaging of the plasma filament. The difference between the plasma parameters measured by the two methods is discussed and analyzed. The main observed difference is in the re-ignition of the jet following the voltage switch-off.