Time resolved spectroscopy of atomospheric plasma jet driven by pulsed power generator

Atmospheric plasma jets, a type of non-thermal plasma, generate various active species such as radicals and ions. As such species are particularly effective at sterilization, research on the sterilization ability of atmospheric plasma jets has been widely conducted, particularly regarding generated active species. This study focuses on active species generated by an atmospheric plasma jet driven by a pulsed power generator. We investigated which active species are present and how the species change with time by measuring the emission spectrum by time-resolved spectroscopy. Two gases (O₂, N₂) were used in the plasma jet for spectral comparison. We also measured the voltage and current waveforms of the plasma jet so as to compare these with the spectrum corresponding to time. Results show that two distinctive spectrum are observed, one during discharge and the other following discharge. This indicates that the active species generated during and following discharge differ. In addition, active species generated by the plasma jet react with ambient air. To further refine the results of our study, a cap was set to the tip of the jet to prevent contact with ambient air, and under this condition, time-resolved spectroscopy was conducted.