AVS 52nd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP9
Effect of Gas Flow on the Gas Temperature in a High Pressure DC Micro-discharge

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Plasma Science and Technology Poster Session
Presenter: F. Doll, University of Houston
Authors: F. Doll, University of Houston
Q. Wang, University of Houston
V.M. Donnelly, University of Houston
D.J. Economou, University of Houston
G.F. Franz, University of Applied Sciences, Germany
Correspondent: Click to Email
The gas temperature of a high pressure DC micro-discharge in mostly Ar or He was deduced by spectroscopic measurements of the rovibrational bands of the second positive system of N2, added as a trace species. The micro-discharge was sustained in a slot between two molybdenum electrodes separated by a distance of 200 microns. The gas temperature in He was significantly lower (350-550 K) than that in Ar (over 1000 K), a reflection of the much higher thermal conductivity of He. Increasing the gas flow rate had little effect on the gas temperature in He, but significantly reduced the gas temperature in Ar. This is consistent with the fact that conductive heat losses dominate in the helium micro-discharge, while heat losses by convection play a role in the Ar micro-discharge. The experimental findings were verified with a two-dimensional flow and heat transfer calculation in the micro-plasma reactor. Finally, the cathode temperature was measured with a thermocouple located 1 mm from the face of the electrode exposed to the plasma. The cathode temperature in the Ar micro-discharge was generally less that 400 K. Work supported by DoE/NSF.