Development of multiwavelength-range fine-resolution spectrometer for hydrogen emissions and its application to large helical device periphery plasmas.

We developed a spectrometer specialized for simultaneous observation of the hydrogen Balmer-alpha, -beta, -gamma lines and the Fulcher-alpha v(')=v(")=2 rovibronic transition band. The spectrometer was optimized for the light input coupled by nine optical fibers having 400 microm core diameters. The spectral resolutions were 0.02-0.03 nm for these wavelength ranges at the entrance slit width of 20 microm. The polarization resolved spectra of these emissions from the peripheral region of large helical device (LHD) plasmas were measured simultaneously and showed the polarization dependence coming from the magnetic field in the LHD plasma.