EUV spectroscopy on NSTX

Abstract

Spectroscopy in the extreme ultraviolet region is important to magnetic fusion research as well as to astrophysics. We report on XEUS (X-ray and Extreme Ultraviolet Spectrometer) and LoWEUS (Long-Wavelength and Extreme Ultraviolet Spectrometer), which operate in the 5–400 Å region on the NSTX (National Spherical Tokamak Experiment) tokamak. The instruments are being used to survey impurities, both for intrinsic elements present in the plasma and for metal impurities resulting from damage to various components. In addition, we have used XEUS and LoWEUS to investigate density-dependent and temperature-dependent emission lines for diagnostic use.