Development of radial neutral beam injection system on LHD

A radial Neutral Beam Injector (NBI) is newly installed on the Large Helical Device (LHD). The aims of the NBI are its usage as a diagnostic NB for charge exchange recombination spectroscopic measurement and using the NB as a heating source for ions in plasmas. A new positive-ion source was developed for this NBI at NIFS. The structure of the cusp field of the source was determined by the numerical code and its performances were verified by experiments. The performances of the developed source fulfill its specification. Especially, the maximum beam current of 102[A] exceeds the requirement of 75[A] about 33[%]