Neutral helium line emission for edge plasma conditions

A diagnostic method for the determination of the neutral helium diffusion coefficient in the edge of magnetically confined fusion plasmas is developed on the basis of emission spectroscopy and population kinetics. The new collisional-radiative numerical code SOPHIA showed that intercombination transitions are extremely important to describe the qualitative and quantitative behaviour of the line emission and the population flow in diffusive plasmas. Corresponding simulations relevant for edge plasma conditions and the NAGDIS-II plasma simulator are discussed.