2018 年 13 巻 p. 3402122
Measurements of radial DD neutron emission profiles by the vertical neutron camera (VNC) are performed in neutral beam-heated deuterium plasmas in the Large Helical Device. The time evolution of the neutron counting rate obtained by VNC is consistent with that of the total neutron emission rate measured by the fission chamber. The radial peak position of line-integrated neutron emission profile shifts outward according to preset magnetic axis positions (Rax_vac) from 3.60 m to 3.90 m. The line-integrated neutron emission profiles measured in the experiment at Rax_vac of 3.60 m, 3.75 m, and 3.90 m are compared with that estimated by a calculation using FIT3D-DD code with considering the line-integration effects. The radial position of the peak in calculation is almost the same as that of in the experiment. However, the profile measured in experiment is wider than that of the calculated profile.
