Development of Impurity Profile Diagnostics in the Ergodic Layer of LHD using 3 m Normal Incidence VUV Spectrometer

Abstract

Space-resolved vacuum ultraviolet (VUV) spectroscopy using a 3 m normal incidence spectrometer has been developed in the large helical device (LHD) to study plasma transport in the ergodic layer by measuring the spatial profile of VUV lines from impurities emitted in the wavelength range of 300-3200 Å. Characteristics of the diagnostics system such as line dispersion, observable region and spatial resolution were evaluated. CIV spectra of 1548.20 2 Å were measured clearly. Intensity and ion temperature profiles were obtained simultaneously using CIV emissions in high-density discharges. Dependencies of the CIV intensity profiles on the electron density and magnetic configurations were observed.