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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 ?. Characteristics of the diagnostics system such as line dispersion, observable region and spatial resolution were evaluated. CIV spectra of 1548.20 × 2 ? 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.

Helium-like argon spectra are measured for plasmas in the Large Helical Device (LHD). The electron temperature Te derived from the intensity ratio of a dielectronic satellite line (1 s2 2p 2P1/2 - 1s2p2 2D3/2) to the resonance line (1 s2 1S0 - 1s2p 1P1) is consistent with the central Te measured with the Thomson scattering method when the electron density ne has a peaked profile. The ion temperature Ti is simultaneously determined from the Doppler broadening width of the resonance line and an establishment of thermal equilibrium between electrons and ions, i.e., Ti = Te, due to increase of ne is experimentally confirmed. The density ratio of lithium-like ion to helium-like ion is determined from fitting of the entire spectrum.