Charge exchange spectroscopy using spatial heterodyne spectrometer in the large helical device

Abstract

In this study, the use of a spatial heterodyne spectrometer (SHS) to measure the toroidal flow velocity ( V f) and the ion temperature [Formula: see text] of the C6+ impurity ion by charge exchange spectroscopy was explored. The instrumental width (IW) of the SHS (aperture size = 16.77 mm2, etendue = 2.9867 mm2 sr) was extrapolated to be 0.09 nm, which is half of the 0.17 nm IW extrapolated for a conventionally used dispersive spectrometer (DS) (aperture size = 2.6 mm2, etendue = 0.2605 mm2 sr). The resulting V f and [Formula: see text] measurements were found to be in good agreement with those measured using the DS.