Temperature profiles of an ablation controlled arc in PTFE: I. Spectroscopic measurements

A wall-stabilized arc in a polytetrafluoroethylene nozzle was investigated. Very similar arc properties as in the ablation dominated high-current phase of SF6 circuit breakers were expected. Spectroscopic measurements of arc temperature profiles were performed. Spectral lines of fluorine and ionized carbon were observed. The side-on intensities of optically thin spectral lines were measured. Abel inversion was applied and the emission coefficient was determined. Temperatures of 16 000 to 18 000 K in the arc centre were obtained at various times of the current pulse. The pressure values were in the range 10-30 bar and arc currents varied from 10 to 20 kA. In the framework of the model, radial temperature profiles were determined with an accuracy of +/- 4%.