TFTR neutral beam ion dump magnet analysis

In running the Tokamak Fusion Test Reactor (TFTR), a desire to improve its capabilities naturally arises. One improvement under consideration is to increase the neutral beam pulse length from 0.5 to 2 s. To achieve this, the heating of the ion beam impinging on the ion dump collector plates must be reduced. This paper describes an analysis that was performed to examine what could be done with the ion dump magnets to reduce the heating by spreading out the beam. The analysis consists of two major parts. One part, performed at the Massachusetts Institute of Technology, covers the magnetic performance of the ion dump magnets. The second part, performed at the Princeton Plasma Physics Lab., covers the particle trajectories and consequent spread patterns of the ion beams on the collector plates.