Fluctuating Helium Emission in Optically Thick Divertor Plasmas

Simulations of the helium radiative properties carried out with the recently developed multi‐level meta‐stable resolved collisional‐radiative code SOPHIA discovered new unique emission lines to analyze optically thick divertor plasmas relevant for ITER. The comparison of their time dependent line emission obtained from the NAGDIS‐II plasma simulator experiments with time dependent temperature probe measurements shows a strong correlation. This indicates that line intensity fluctuations can be transformed to the important quantities of density and temperature fluctuations. A transformation method based on integral line intensity ratios which can be recorded with high time resolution is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)