Modeling of Beam Transport, Secondary Emission and Interactions With Beam-Line Components in the ITER Neutral Beam Injector

The injection of high energy beams of neutral particles is a fundamental method for plasma heating to ignition in the advanced fusion devices. The requirements of the heating neutral beam to be installed on ITER Tokamak and of the full scale prototype megavolt ITER injector and concept advancement represent a large extrapolation from existing devices. An extensive work on numerical modeling is required to optimize the final design and the injector performances. As the power and charge deposition onto components originates from several sources (primary beam, co-accelerated electrons, and secondary production by beam-gas, beam-surface, and electron-surface interaction), the beam propagation along the beam line is simulated by a comprehensive 3-D model of the beam transport and power deposition phenomena along the injector. The code calculates the particle motion in electromagnetic fields, including the secondary production, the reionization of the beam, and the interactions with the surfaces. The preliminary calculations here reported are focused on the phenomena occurring in the residual ion dump.