Charge-Exchange Spectroscopy with Pitch-Controlled Double-Slit Fiber Bundle on LHD

The systems of charge-exchange spectroscopy (CXS) have been improved on the Large Helical Device (LHD). Pitch-controlled fiber bundles give faster readout time, and double-slit fiber bundles increase the number of channels that can be obtained with a single charge-coupled device detector. The evolutions of ion temperature with a sampling time of 10 ms are obtained, and profiles of ion temperature, toroidal rotation velocity, and density of carbon impurity with data at 51 spatial points are measured with the improved CXS systems.