DEVELOPMENT OF HIGH-POWER NEGATIVE-ION SOURCES FOR FUSION-RESEARCH ATJAERI

Recent progress regarding high power negative-ion source development f or fusion research at JAERI is described. Using the cesium-seeded volu me production-type negative-ion sources with an electrostatic accelera tion system, a stable production of multiampere negative hydrogen/deut erium ion beams and a high energy acceleration of negative hydrogen io ns of 0.2 A up to 350 keV have been demonstrated. On the basis of this recent progress, the construction of a 500 keV, 22 A, deuterium negat ive-ion source for a neutral beam injection system for the JT-60 tokam ak was initiated. Additionally, a 1 MeV, 1 A Cockcroft-Walton-type tes t facility has been prepared in order to demonstrate high current nega tive ion acceleration up to 1 MeV. Through these research and developm ent activities, the high power negative-ion source technology sufficie nt for the realization of a neutral beam injection system for a fusion experimental reactor such as the International Thermonuclear Experime ntal Reactor, is in the planning stages.