PPPS-2013: Abstract Submission: Spectral analysis of arc radiation with high optical thickness

Summary form only given. High-pressure arcs in copper vapour in the range of peak currents between 2 to 10 kA are studied by optical emission spectroscopy. The arc experiments¹ are operated in air at atmospheric pressure, and the copper vapour is generated by erosion of the copper electrodes (cathode and anode) caused by the large energy transfer from the arc. The arc radiation in the visible part of the spectrum is dominated by line radiation of copper atoms and ions. Depending on arc current and copper evaporation the lines show quite different line width and optical thickness up to self-absorption. In some cases an almost continuous spectrum is observed. The spectroscopic study is aimed at the determination of the plasma temperature and copper density in these arcs. It is demonstrated, that quite different methods of line analysis like Boltzmann plot of optical thin lines and Bartels method to analyse lines with self-reversal can be applied under specific arc operating conditions. However, increasing optical depth may hamper Boltzmann plot method whereas norm maximum of particle densities at high temperatures limits applicability of Bartels method. Therefore temperature determination requires an explicit consideration of the radiation absorption by radiation transport simulations. The analysis is focussed on the comparison of the arc properties near to the cathode and the anode. Temperatures in the range from 10000 to 18000 K have been obtained.