SPACE-RESOLVED MEASUREMENTS OF TITANIUM SOFT-X-RAY EMISSIONS FROM FTUTOKAMAK PLASMAS

X-ray spectra due to intrinsic titanium are obtained on the FTU tokama k using a crystal spectrometer with spatial resolution. He-like ion sp ectra are observed for ohmic and lower hybrid (LH) heated high density plasmas. In a single discharge four spectra are recorded with differe nt lines of sight. With a post-process subroutine of an impurity trans port code, synthetic spectra are built up and compared with the experi mental ones. Line intensity ratios with respect to the resonance w lin e are studied. For the intercombination lines x and y the agreement be tween experiment and simulation is satisfactory, whereas for the forbi dden line z the simulations give line ratios higher than the experimen tal values by 25 to 40%. The electron temperatures T-e deduced from th e ''dielectronic'' satellite line ratios agree with the corresponding values from standard T-e diagnostics. For the ''collisional'' satellit e q the line intensity ratios are sensitive to the titanium ion charge distribution in the plasma core and, consequently, to the impurity tr ansport parameters. Diffusion coefficients D equal to 0.7 and to 2.0 m (2)/s are obtained in the plasma core of, respectively, ohmic and LH h eated plasmas. The impurity confinement time tau(p) is deduced from th e diffusion coefficient D and compared with the predictions of a tau(p ) scaling law.