Analysis of difference in Hα spectral line profiles between attachment and detachment plasmas in LHD

The sustainable detachment has been achieved in LHD. The line-averaged electron density of the detachment plasmas is typically over 1.0 × 1020 m−3. The difference in the broad component of the Hα spectral line profiles between the attachment and detachment plasmas has been observed. In attachment, the divertor flux much affects the neutral hydrogen generation and the large inward flow up to 1.5 × 104 m/s seemed to be due to the reflection is observed. In detachment, the much smaller flow velocity along the sight lines and the lower Doppler temperature are observed. These observations represent the drastic reduction of the divertor flux and the decrease of the edge electron temperature involved with detachment.