摘要
Large size hydrogen neutral beam injectors （NBI） used a negative ion source （NNBI） as well as a proton source （PNBI） were developed for the large helical device （LHD）. The injected power from NNBI and PNBI have reached 16 MW and 6.8 MW, respectively, These injected powers have outstripped the nominal beam powers. A diagnostic system of beam-emitted hydrogen visible spectrum has been installed along the beam injection axis to estimate the energy fraction on PNBI. The full energy beam component is about half which is equivalent to 70% of injected beam power. The attenuation of high energy neutral beam is also observed on NNBI. The peak density distribution is effective to increase beam deposition power.
Large size hydrogen neutral beam injectors （NBI） used a negative ion source （NNBI） as well as a proton source （PNBI） were developed for the large helical device （LHD）. The injected power from NNBI and PNBI have reached 16 MW and 6.8 MW, respectively, These injected powers have outstripped the nominal beam powers. A diagnostic system of beam-emitted hydrogen visible spectrum has been installed along the beam injection axis to estimate the energy fraction on PNBI. The full energy beam component is about half which is equivalent to 70% of injected beam power. The attenuation of high energy neutral beam is also observed on NNBI. The peak density distribution is effective to increase beam deposition power.
基金
the budget for NIFS08ULBB501 of Japan
the JSPS-CAS Core-University program in the field of Plasma and Nuclear Fusion
