VACUUM UV SPECTROSCOPY AND IMPURITY BEHAVIOR IN TOKAMAK AND STELLARATOR PLASMAS

An overview of applications of vacuum UV (VUV) spectroscopy to studies of fusion plasmas is presented. This spectral region is usually consi dered to extend from 10 to 2000 Angstrom. Most impurity studies in cor e plasmas and in diverters rely on measuring the intensities of the br ight resonance lines that lie in this wavelength range. In the core, t hese data are supplemented by emissions from charge exchange excitatio n to determine concentrations of fully stripped low-Z ions. Determinat ions of individual impurity radiative losses and densities are carried out with the aid of one-dimensional codes in which transport coeffici ents are adjusted until the modelled intensities are well matched to e xperimental observation. Analysis of divertor spectra presents special difficulties, because of the inherently two- or three-dimensional nat ure of the radiation patterns. In addition to impurity studies, VUV li nes are used to determine electron and ion temperatures, and plasma ro tation. (C) 1997 Elsevier Science S.A.