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.