Radiative aspects of the ablation-stabilized arc in polyethylene tube

The arcs burning through polyethylene tubes are observed photographically and spectroscopically. The arc currents are 5~15 A DC. The tubes are of 2~6-mm inner diameter and are 15 mm in length. Color photographs of the arc reveal that the arc column consists of three emission regions: a red-colored core and blue-colored and orange-colored layers. The spectral intensity of the arc column is surveyed for wavelengths from 300 to 900 nm, and the radial distributions of specific spectral intensities are measured for various arc currents and tube diameters. The results indicate that the spectra from the three emission regions are of hydrogen atoms, carbon molecule, and continuum, respectively. The radial temperature distributions of the arcs are estimated from the spectral intensities of the hydrogen atom and the carbon molecule. The results show that the polyethylene arc takes a typical temperature distribution of ablation-controlled arc