Spectroscopic studies on impurity transport of core and edge plasmas in LHD

Shigeru Morita, Motoshi Goto, Sadatsugu Muto, Ryuji Katai, Hisamichi Yamazaki, Hideaki Nozato, Atsushi Iwamae, Makoto Atake, Takashi Fujimoto, Atsushi Sakaue, Hiroaki Nishimura, Ikuya Sakurai, Chiho Matsumoto, Akihiro Furuzawa, Yuzuru Tawara, Mitsutoshi Aramaki, Yuji Okumura, Koichi Sasaki, Xianzu Gong, Jiangang LiBaonian Wan, Zhengying Cui

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Abstract

Spectroscopic diagnostics have been extensively developed for studies of impurity and neutral particle transports at core and edge plasmas in LHD. Diagnostics of core plasmas are similar to a tokamak case, i.e., Zeff from visible bremsstrahlung, K-x-ray measurements from x-ray spectroscopy using Si(Li) detectors and a compact crystal spectrometer, and high-Z impurity diagnostics from VUV spectroscopy using a flat-field EUV spectrometer. A combination of impurity pellet injection and visible bremsstrahlung is an active tool for determination of the diffusion coefficient D and convective velocity V. Using this tool the spatial structures of D and V are obtained and discussed with a neoclassical effect. On the other hand, the spectroscopic method for edge diagnostics is considerably different from the tokamak case because of the existence of a thick ergodic layer in addition to the x-points necessarily included into the diagnostic chord view. In order to break this negative situation, Zeeman and polarization spectroscopy are adopted to LHD edge plasmas. As a result, 2-dimensional emission contours of HeI and Hα are successfully obtained. Laser absorption spectroscopy is tried to measure hydrogen neutrals directly. Radial profiles of edge impurities are also measured with a mirror-assembled 3 m VUV spectrometer. Recent results of and progress in LHD spectroscopy are briefly reviewed.

Original languageEnglish
Article number13
Pages (from-to)55-60
Number of pages6
JournalPlasma Science and Technology
Volume8
Issue number1
DOIs
Publication statusPublished - 01-01-2006

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All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Morita, S., Goto, M., Muto, S., Katai, R., Yamazaki, H., Nozato, H., Iwamae, A., Atake, M., Fujimoto, T., Sakaue, A., Nishimura, H., Sakurai, I., Matsumoto, C., Furuzawa, A., Tawara, Y., Aramaki, M., Okumura, Y., Sasaki, K., Gong, X., ... Cui, Z. (2006). Spectroscopic studies on impurity transport of core and edge plasmas in LHD. Plasma Science and Technology, 8(1), 55-60. [13]. https://doi.org/10.1088/1009-0630/8/1/13