title: Diagnostics for molybdenum and tungsten erosion and transport in NSTX-U.
abstract: A comprehensive set of spectroscopic diagnostics is planned in the National Spherical Torus Experiment Upgrade to connect measurements of molybdenum and tungsten divertor sources to scrape-off layer (SOL) and core impurity transport, supporting the installation of high-Z plasma facing components which is scheduled to begin with a row of molybdenum tiles. Imaging with narrow-bandpass interference filters and high-resolution spectroscopy will be coupled to estimate divertor impurity influxes. Vacuum ultraviolet and extreme ultraviolet spectrometers will allow connecting high-Z sources to SOL transport and core impurity content. The high-Z diagnostics suite complements the existing measurements for low-Z impurities (carbon and lithium), critical for the characterization of sputtering of high-Z materials.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: F
authors.initials: F
authors.lastname: Scotti
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: V A
authors.initials: VA
authors.lastname: Soukhanovskii
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Weller