Status of the Negative Ion Based Heating and Diagnostic Neutral Beams for ITER

Abstract

The current baseline of ITER foresees 2 Heating Neutral Beam (HNB’s) systems based on negative ion technology, each accelerating to 1 MeV 40 A of D− and capable of delivering 16.5 MW of D0 to the ITER plasma, with a 3rd HNB injector foreseen as an upgrade option [1]. In addition a dedicated Diagnostic Neutral Beam (DNB) accelerating 60 A of H− to 100 keV will inject ≈15 A equivalent of H0 for charge exchange recombination spectroscopy and other diagnostics. Recently the RF driven negative ion source developed by IPP Garching has replaced the filamented ion source as the reference ITER design. The RF source developed at IPP, which is approximately a quarter scale of the source needed for ITER, is expected to have reduced caesium consumption compared to the filamented arc driven ion source. The RF driven source has demonstrated adequate accelerated D− and H− current densities as well as long‐pulse operation [2, 3]. It is foreseen that the HNB’s and the DNB will use the same negative ion source. Experiments ...