Benchmarking atomic physics models for magnetically confined fusion plasmaphysics experiments

In present magnetically confined fusion devices, high and intermediate Z im purities are either puffed into the plasma for divertor radiative cooling e xperiments or are sputtered from the high Z plasma facing armor. The benefi cial cooling of the edge as well as the detrimental radiative losses from t he core of these impurities can be properly understood only if the atomic p hysics used in the modeling of the cooling curves is very accurate. To this end, a comprehensive experimental and theoretical analysis of some relevan t impurities is undertaken. Gases (Ne, Ar, Kr, and Xe) are puffed and nonga ses are introduced through laser ablation into the FTU tokamak plasma. The charge state distributions and total density of these impurities are determ ined from spatial scans of several photometrically calibrated vacuum ultrav iolet and x-ray spectrographs (3 - 1600 Angstrom), the multiple ionization state transport code transport code (MIST) and a collisional radiative mode l. The radiative power losses are measured with bolometery, and the emissiv ity profiles were measured by a visible bremsstrahlung array. The ionizatio n balance, excitation physics, and the radiative cooling curves are compute d from the Hebrew University Lawrence Livermore atomic code (HULLAC) and ar e benchmarked by these experiments. (Supported by U. S. DOE Grant No. DE-FG 02-86ER53214 at JHU and Contract No. W-7405-ENG-48 at LLNL.) (C) 1999 Ameri can Institute of Physics. [S0034-6748(99)65201- 7].