Magnetic Axial Dependency of Hα Emission Location in Peripheral Plasmas of Large Helical Device as Determined by Plasma Polarization Spectroscopy

抄録

The behavior of hydrogen neutral particles in and around the ergodic layer of Large Helical Device plasmas has been investigated through Hα emission spectral line profiles using plasma polarization spectroscopy (PPS). The PPS technique enables us to quantitatively evaluate emission locations, atomic temperatures and velocity components along the line-of-sight (LOS) for both inner and outer peripheral regions. The emission locations and the LOS components of atomic velocities are determined by varying the magnetic field axis R_ax from 3.60 m to 4.00 m, shot by shot. The high intensity region of Hα emissions is localized in the inner ergodic layer for the inward configuration. With an increase in R_ax, the high intensity region of Hα emission moves outward.