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Plasma and Fusion Research
Volume 3, S1074 (2008)
Regular Articles
- National Institute for Fusion Science,322-6 Oroshi-cho, Toki 509-5292, Japan
- 1)
- Kyoto University Pioneering Research Unit for Next Generation, Gokasho, Uji 611-0011, Japan
- 2)
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
Abstract
The creation of holes and clumps in an energetic ion energy spectrum associated with Alfvén eigenmodes was examined using the neutral particle analyzer (NPA) on the LHD shot #47645. The difference in slowingdown times between the holes and clumps suggested that the energetic ions were transported over 10% of the plasma minor radius. The spatial profile and frequency of the Alfvén eigenmodes were analyzed with the AE3D code. The phase space structures of the energetic ions on the NPA line-of-sight were investigated with Poincaré plots, where an oscillating Alfvén eigenmode was employed for each plot. The phase space regions trapped by the Alfvén eigenmodes appeared as islands in the Poincaré plots. The radial width of the islands corresponded to the transport distance of the energetic ions. Since island width depends on Alfvén eigenmode amplitude, it was found that Alfvén eigenmodes with amplitude δBr/B ∼ 10-3 transported energetic ions over 10% of the minor radius.
Keywords
energetic ion transport, Alfvén eigenmode, Poincaré plot, LHD, neutral particle analyzer
Full Text
References
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- [2] D.A. Spong and Y. Todo, “Shear Alfvén spectrum and mode structures for 3D configurations,” 49th Annual Meeting of the Division of Plasma Physics (12-16 November 2007, Orlando), PP8.00098.
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- [4] Y. Todo, H.L. Berk and B.N. Breizman, Phys. Plasmas 10, 2888 (2003).
This paper may be cited as follows:
Yasushi TODO, Noriyoshi NAKAJIMA, Masaki OSAKABE, Satoshi YAMAMOTO and Donald A. SPONG, Plasma Fusion Res. 3, S1074 (2008).