Observations of the vacuum ultraviolet and x-ray brightness profiles of Fe, Ni, and Ge in magnetically confined fusion plasmas - art. no. 036406

The spatial brightness profiles of emission lines for the K-like through He -like ionization states of Fe, Ge, and Ni have been measured during a set o f experiments in which Fe and Ge were introduced into FTU tokamak plasmas b y using the laser blowoff technique. Nickel was an intrinsic impurity obser ved during these experiments that was sputtered from the inconel limiter. T he brightness profiles were measured by spatially scanable, photometrically calibrated vacuum ultraviolet and x-ray spectrometers that covered the 1 t o 1700 Angstrom region. Simulations of these profiles and the time evolutio n of the laser blowoff's were performed with the MIST transport code using several sets of atomic physics compilations [ADPAK (originally in MIST), Ar naud and Raymond (AR92), Arnaud and Rothenflug (AR85), Mazzotta et al., and Mattioli (an extension to Mazzotta)], The goal was to determine which set of available rates could best simulate the measured spatial brightness prof iles and the charge state balance in the plasma. The Mazzotta et al. (for F e and Ni), the Mattioli (for Ge), and the AR92 (for Fe only) rates adequate ly simulated the He-, Li-, Be-, Na-, Mg-like ionization states. The F- to B -like charge states could not be simulated by these compilations unless the relevant dielectronic rates were multiplied by a factor of 2. The ADPAK ra tes could not adequately predict any of the charge states of Fe, Ge, or Ni.