Spectroscopy of plasma of electric arc discharge between Cu-Mo composite electrodes

This work is devoted to the study of thermal plasma of electric arc discharges between composite Cu-Mo electrodes by optical diagnostic techniques. The electrodes were fabricated from copper–molybdenum composite materials. The arc discharge was ignited in an argon flow at a direct current of 3.5 A and a discharge gap of 8 mm. The absolute intensities of the spectral lines emitted by the plasma were registered in the spectral range of 430–650 nm. Radial distributions of key plasma parameters, namely excitation temperature and number densities of metals, were determined. For this purpose, the Boltzmann plot technique was applied using selected spectral lines of Cu I and Mo I. Particular attention was paid to the applicability of the local thermodynamic equilibrium assumption in the arc plasma under such discharge conditions.