Analysis of impurity content and transport in tokamak plasmas using low-resolution XUV spectra

Two experiments were performed to determine whether impurity content and transport information could be extracted from low-resolution XUV spectra recorded from a simple spectroscopic diagnostic that utilized a flat multilayer mirror as the dispersive element. The first experiment, at the DIII-D tokamak, compared MLM spectra to higher-resolution spectra and found that the low-resolution MLM spectra were sufficient to distinguish changes in impurity emission patterns. The results demonstrated the feasibility of building simple MLM-based diagnostics for impurity monitors in the harsh environment of future tokamaks. The second experiment, at the Texas Experimental tokamak, compared MLM spectra to those produced by an impurity transport code coupled to a collisional-radiative model. The comparison showed that it is possible to distinguish changes in impurity transport from low-resolution MLM spectra.