HIGH-ENERGY NEGATIVE-ION BASED NEUTRAL BEAM INJECTION SYSTEM FOR JT-60U

On the basis of recent progress in the research and development of a high current and high energy negative-ion source, the construction of a 500 keV negative-ion based neutral beam injection (NBI) system for JT-60U has begun to demonstrate a mega-amp level NE current drive at high plasma density and to study high energy beam heating in reactor-grade plasmas. The specification of the NBI system is as follows: a beam energy of 500 keV, an injection power of 10 MW, a beam duration time of 10 s, beam species of deuterium or hydrogen. The neutral beam of 10 MW is injected in a tangential codirection with a single beamline that has two negative ion sources. The construction of the negative-ion based NBI system will be completed in 1996, and NE current drive and plasma core heating experiments will start immediately in JT-60U.