Diagnostics for liquid lithium experiments in CDX-U

A flowing liquid lithium first wall or divertor target could virtually elim inate the concerns with power density and erosion, tritium retention, and c ooling associated with solid walls in fusion reactors. To investigate the i nteraction of a spherical torus plasma with liquid lithium limiters, large area divertor targets, and walls, discharges will be established in the Cur rent Drive Experiment-Upgrade (CDX-U) where the plasma-wall interactions ar e dominated by liquid lithium surfaces. Among the unique CDX-U lithium diag nostics is a multilayer mirror (MLM) array, which will monitor the 13.5 nm LiIII line for core lithium concentrations. Additional spectroscopic diagno stics include a grazing incidence extreme ultraviolet (XUV) spectrometer (S TRS) and a filterscope system to monitor D-alpha and various impurity lines local to the lithium limiter. Profile data will be obtained with a multich annel tangential bolometer and a multipoint Thomson scattering system confi gured to give enhanced edge resolution. Coupons on the inner wall of the CD X-U vacuum vessel will be used for surface analysis. A 10 000 frame per sec ond fast visible camera and an IR camera will also be available. (C) 2001 A merican Institute of Physics.