Analysis of the Dα spectral line shape on the carbon limiter insertion experiments in Heliotron J

In order to investigate the velocity distribution function of deuterium atoms, which gives information about the recycling process, in the Heliotron J edge plasma region, spectral line shapes of Dα emitted in front of a carbon limiter have been measured with a high-resolution spectrometer. Measured spectral profiles have an asymmetric structure and are decomposed into the broad and narrow Gaussian components. The central wavelengths of each component shift toward the blue side. The intensity distribution is similar to the footprint of the magnetic field lines on the limiter surface. The emission from reflected atoms affects the intensity distribution of the broad component.