Toroidally symmetric/asymmetric effect on the divertor flux due to neon/nitrogen seeding in LHD

H. Tanaka; G. Kawamura; S. Masuzaki; M. Kobayashi; T. Akiyama; B.J. Peterson; K. Mukai; R. Sano; S.Y. Dai; R. Sakamoto; T. Morisaki; N. Ohno

Nuclear Materials and Energy (Aug 2017)

Toroidally symmetric/asymmetric effect on the divertor flux due to neon/nitrogen seeding in LHD

H. Tanaka,
G. Kawamura,
S. Masuzaki,
M. Kobayashi,
T. Akiyama,
B.J. Peterson,
K. Mukai,
R. Sano,
S.Y. Dai,
R. Sakamoto,
T. Morisaki,
N. Ohno

Affiliations

H. Tanaka: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan; Corresponding author.
G. Kawamura: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
S. Masuzaki: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
M. Kobayashi: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
T. Akiyama: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
B.J. Peterson: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
K. Mukai: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
R. Sano: National Institutes for Quantum and Radiological Science and Technology, Naka, Ibaraki 311-0193, Japan
S.Y. Dai: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, PR China
R. Sakamoto: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan; Department of Fusion Science, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
T. Morisaki: National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
N. Ohno: Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603, Japan

Journal volume & issue: Vol. 12
pp. 241 – 246

Abstract

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Toroidal distributions of divertor particle flux during neon (Ne) and nitrogen (N2) seeded discharges were investigated in the Large Helical Device (LHD). By using 14 toroidally distributed divertor probe arrays, which were positioned at radially inner side where the divertor flux concentrates in the inward-shifted magnetic axis configuration, it is found that Ne puffing leads to toroidally quasi-uniform reduction of divertor particle fluxes; whereas toroidally localized reductions were observed with N2 puffing. The toroidally asymmetric reduction pattern with N2 puffing is strongly related to the magnetic field structure around the N2 puffing port. Assuming that nitrogen particles do not recycle, EMC3-EIRENE simulation shows similar reduction pattern with the experiment around the N2 puffing port. Keywords: Impurity seeding, LHD, Toroidal divertor probe arrays, Neon, Nitrogen, EMC3-EIRENE

Published in Nuclear Materials and Energy

ISSN: 2352-1791 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-materials-and-energy/

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