Powerful 160-Kev Neutral Deuterium Beam Injector For Application In Fusion-Research

A 160-keV neutral deuterium beam injector has been developed for plasma heating in JET (Joint European Torus) fusion experiment. This injector has been reliably operated at 5.9-MW extracted deuterium ion beam power (37-A, 160-keV ion beam) and 5-s pulse duration. The neutral beam power was 1.75 MW corresponding to an overall neutral injector power efficiency of 30%. The beam divergence was 0.6°. The ion beam was accelerated with a three-grid multiaperture system (aperture diameter φ=11 mm). The accelerating gap length was 24 mm. The extracted deuterium ion current density amounted to 150 mA/cm2. Grid and source body power loadings were acceptable for quasi-steady-state operation.