ARC DISCHARGE SOURCES

This report summarizes models for the high energy pulsed arc discharge used for high energy laser pumping. Homogeneous temperature models are discussed in which the radiant emission is balanced by the electrical power input. These models have been evaluated at various energy levels for the temperature which has been measured within the arc assuming local thermal equilibrium. The models included the continuum spectral absorptivity calculated according to Biberman Norman using the Zeta factor of Schluter. There was found to be a semi-quantitative agreement between the Zeta factor observed experimentally, and those of Biberman Norman, and of Schluter. The spectral transmissivity as a function of current density calculated from the models showed reasonable agreement with the experimental values of Emmett, Schawlow, and Weinberg in the visible and the ultraviolet, but differ widely in the infrared due to the strong infrared lines of xenon. Measurements of the time- resolved profiles of lines in the infrared, of the radial distribution of the spectral radiance in the ultraviolet, and of the electrical conductivity are also discussed. These measurements provide a means for determining the temperature dependence of these quantities within these arcs. The ultraviolet radial profiles indicate that the arc is relatively homogeneous for the range of current densities and pressures studied.