Negative ion optics benchmark experiments at NIFS

Negative ions are fundamental to produce high energy neutral beams used to he at the plasma in fusion experiments . The negative ions so urces for reactor class fusion devices represent a huge extrapolation from existing device, hence the use of modelling tools i s mandatory. In particular, the design of the neutral beam injector of the ITER experiment was strongly based on the results of n umerical codes. In this report we c ompare the models with the results of real experiments, carried out during dedicated campaigns at the R&D negative ion source (RNIS) hosted at the national institute for fusion science (NIFS), in Japan.