(FT/P2-27) Development of Long Pulse Neutral Beam Injector on JT-60U for JT-60SA

M.H. Hanada1), Y. Ikeda1), L. Grisham12), S. Kobayashi3)
1) Japan Atomic Energy Agency, Naka, Japan
2)Princeton Plasma Physics Laboratory, Princeton, NJ, USA
3)Saitama University, Saitama, Japan

Abstract.  Long pulse neutral beam injectors (NBIs) are being developed to realize 100 s D0 injection at 34 MW in total for JT-60SA. Significant progress has been made in the development of the negative-ion-based NBI (N-NBI) where a 10 MW injection is required. In the N-NBI, a long pulse injection up to ∼30 s was achieved at 1 MW using one ion source. The time response of the neutron flux from the plasma indicates constant D0 power without degradation. In the R&D's, a field shaping plate (FSP) for tuning the beamlet steering angle was newly designed and tested in the JT-60U negative ion source. The FSP succeeds in the reduction of the grounded grid power loading to 6% of the drain power in the acceleration power supply. This power loading is an allowable level for full D- ion beam for JT-60SA. Moreover, the power loading of the electrons ejected from the JT-60U negative ion source into the beamline is measured to be as small as 2.6% of the drain power, and can be acceptable for JT-60SA.

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