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 SF 6 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%.