Electrode sheath model for an argon free burning arc discharge at very high pressure and low intensity

International audienceIn this paper, a two-temperatures model has been applied to the near cathode and anode layers for a very high- pressure (>>105 Pa), low-current (< 1 A) argon free burning arc discharge in a tip-tip configuration. Different theories that has been proposed in the literature regarding cathode and anode phenomena were reviewed first. The model behavior has been studied in different pressure and current conditions and the results were compared to the model proposed in the literature. Typical results obtained from this model show that the voltage drop in the cathode layer varies between 1 to 150 V for cathode temperatures of 5000 and 3000 K, respectively. For the anode layer, typical 3-14 V voltage drops were observed. Very high pressure influence on the voltage drop clearly appear for pressures up to 10 MPa on the cathode layer. In the anode layer, high pressure seems to not have a relevant role. A 9 and 6 V maximal voltage drop at the near- cathode zone has been obtained for pressures equal to 0.1 MPa and 10 MPa respectively (electrode wall temperature, 4000 K). In the anode layer, maximal total voltage drop was estimated around 5 V