Positive-ion based NBI for JT-60U
Picture and performance of ion source
Positive Ion Source for JT-60U
The positive-ion source for JT-60U delivers a beam of 35A at 100keV with deuterium. The proton ratio of the beam is 90%, and beam divergence is around one degree in e-folding value. Since two ion sources are mounted on a beamline, 28 ion sources in total are used in the positive-ion based NBI for JT-60U.
Beam energy : 100keV
Beam current : 40A
Beam species : D/H/3He/4He
Extraction area : 12 × 27 cm2
D+ : D2+ : D3+ = 90 : 7 : 3
No of ion sources : 28
Design values and achieved values of the positive-ion based NB
Achieved values of positive-ion based NBI for JT-60/JT-60U
The NBI for JT-60 started beam injection opearation in 1986 with hydrogen beam. The every NBI system in original design is perpendicular injection against plasma axis. In 1990~1991, four beamlines out of 14 units have been modified from perpendicular to tangential injection by manifacturing a newly designed beamline tanks, at the same time the modification for deuterium beam, high energy beam opeartion up to 120keV have been conducted.
The following table is shown the achieved values of NBI system performance compared with the design values.
Progress of injection power
Progress of injection power in JT-60 Positive-ion based NBI
An injection power of 40MW has been achieved with D0 beam in 1996.
