ON THE PLASMA PROPERTIES OF DIFFUSE COPLANAR SURFACE BARRIER DISCHARGE IN HUMID NITROGEN AND HUMID AIR STUDIED BY OPTICAL EMISSION SPECTROSCOPY
| Authors | |
|---|---|
| Year of publication | 2009 |
| Type | Article in Proceedings |
| Conference | 4th International Workshop on Cold Atmospheric Pressure Plasmas |
| MU Faculty or unit | |
| Citation | |
| Field | Plasma physics |
| Keywords | coplanar barrier discharge; optical emission spectroscopy; humidity; nitrogen; technical air |
| Description | In this work we investigated the influence of working gas humidity on the plasma properties of diffuse coplanar surface barrier discharge (DCSBD). As working gases pure nitrogen and technical air admixed with the vapors of distilled water were used. We measured the intensities of second positive system of nitrogen (band 2-0 at 297.7 nm) and integrated emissions of OH (R(1) and R(2) at 306.5 nm), NO-gamma system (band 0-3 at 259 nm) and 0 intensities (at 777.4 nm). The relative humidity of gas was measured and from these measurements the absolute humidity of the gas was estimated. We observed strong dependence of gas humidity on DCSBD behavior. The discharge pattern and emission spectra differs substantially in the case of nitrogen and technical air respectively. In case of nitrogen we observed transition from diffuse-like discharge to sparse-filamentary discharge in higher humidity region and decrease of the OH/N(2) and NO/N(2) intensity ratios. In the case of technical air the discharge remains diffuse for higher value of humidity and then became stable with very dense filamentary pattern. The ratios of OH/N(2) and NO/N(2) intensity are increasing in that case. From the measurements we can conclude that the absolute humidity of working gas plays important role in the DCSBD behavior. Hence the influence of absolute humidity of working gas has to be studied in the case of materials processing applications. |
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