Diagnostics for molybdenum and tungsten erosion and transport in NSTX-U

A comprehensive set of spectroscopicdiagnostics is planned in the National Spherical Torus Experiment Upgrade to connectmeasurements ofmolybdenum andtungstendivertor sources to scrape-off layer (SOL) and core impurity transport, supporting the installation of high-Zplasma facing components which is scheduled to begin with a row ofmolybdenum tiles. Imaging with narrow-bandpass interference filters and high-resolution spectroscopy will be coupled to estimatedivertor impurity influxes. Vacuum ultraviolet andextreme ultravioletspectrometers will allow connecting high-Z sources to SOL transport and core impurity content. The high-Zdiagnostics suite complements the existingmeasurements for low-Z impurities (carbon and lithium), critical for the characterization ofsputtering of high-Z materials.

Source: Review of Scientific Instruments - October 13, 2016 Category: Physics Authors: F. Scotti, V. A. Soukhanovskii and M. E. Weller Source Type: research