Estimate of the Deposition Profile of Carbon Pellets Using a High-Speed VUV Imaging System in the LHD

The deposition profile of the impurity pellet is measured by a two-dimensional fast- framing vacuum ultraviolet (VUV) camera system in the large helical device (LHD). The fast framing camera selectively measures the emission from the hydrogen-like ions of carbon (C VI) with a frame rate of several kHz. From the emission profile of the hydrogen-like carbon ions, which are in the process of ionization, the initial deposition profile of the carbon is estimated using a simple one-dimensional transport model.