Spectral intensity distribution of oxygen atom in a plasma plume

Abstract

Low temperature plasma generated in plasma plume discharge at atmospheric pressure has prosperous application fields in industry because the vacuum device can be dispensable and some complex materials can be treated in three dimensions by this plasma plume. A stable plasma plume was generated in atmospheric pressure air in the present paper by using a plasma needle discharge device. It was found by spectral measurement that there are some spectral lines emitted from oxygen atom such as 777.5 and 844.6 nm in the optical emission spectra of the plasma plume. This phenomenon indicates that oxygen atom with high chemical activity was generated in the air discharge at atmospheric pressure. The spatial distribution of the spectral intensity from the oxygen atom was investigated by spectroscopic method. Results show that the spectral intensity from oxygen atom near the needle electrode was much higher than that in other regions. In order to explain this experimental phenomenon, spatial-resolved signals emitted from the plume were detected by using photomultiplier tubes. It was found that the width of light pulse near the needle electrode was much bigger than that in other regions. These results are important for the application of plasma plume in industry such as sterilization and disinfection fields.