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Title: Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD

Here, surveys of the ion and electron heat transports of neutral beam (NB) heating plasma were carried out by power balance analysis in He and H rich plasma at LHD. Collisionality was scanned by changing density and heating power. The characteristics of the transport vary depending on collisionality. In low collisionality, with low density and high heating power, an ion internal transport barrier (ITB) was formed. The ion heat conductivity (χ i) is lower than electron heat conductivity (χ e) in the core region at ρ < 0.7. On the other hand, in high collisionality, with high density and low heating power, χ i is higher than χ e across the entire range of plasma. These different confinement regimes are associated with different fluctuation characteristics. In ion ITB, fluctuation has a peak at ρ = 0.7, and in normal confinement, fluctuation has a peak at ρ = 1.0. The two confinement modes change gradually depending on the collisionality. Scans of concentration ratio between He and H were also performed. The ion confinement improvements were investigated using gyro-Bohm normalization, taking account of the effective mass and charge. The concentration ratio affected the normalized χ i only in the edge region (ρmore » ~ 1.0). This indicates ion species effects vary depending on collisionality. Turbulence was modulated by the fast ion loss instability. The modulation of turbulence is higher in H rich than in He rich plasma.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [4] ;  [5] ;  [6] ;  [6] ;  [6] ;  [6] ;  [4] ;  [6] ;  [4] ;  [6] ;  [6] ;  [6] ;  [4] ;  [4] more »;  [7] ;  [8] ;  [9] ;  [10] « less
  1. National Inst. for Fusion Science (NIFS), Toki (Japan); Kyushu Univ. (Japan). Dept. of Advanced Energy Engineering
  2. National Inst. for Fusion Science (NIFS), Toki (Japan); Nagoya Univ. (Japan). Graduate School of Science
  3. Kyoto Univ. (Japan). Dept. of Nuclear Engineering
  4. National Inst. for Fusion Science (NIFS), Toki (Japan); SOKENDAI, Toki (Japan). The Graduate Univ. for Advanced Studies
  5. Australian National Univ., Canberra, ACT (Australia). Plasma Research Lab. and Research School of Physics and Engineering
  6. National Inst. for Fusion Science (NIFS), Toki (Japan)
  7. Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy
  8. Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP); Novosibirsk State Univ. (Russian Federation)
  9. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  10. Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP); Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of)
Publication Date:
Grant/Contract Number:
NIFSULHH013; NIFS10ULRR702; NIFSULHH004; NFSULHH005; NIFSULHH02; NIFSULHH028; NIFS16KLER045; NIFS14UNTT006
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 11; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); National Inst. for Fusion Science (NIFS), Toki (Japan)
Sponsoring Org:
USDOE
Contributing Orgs:
the LHD Experimental Group
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
OSTI Identifier:
1474420

Tanaka, K., Nagaoka, K., Murakami, S., Takahashi, H., Osakabe, M., Yokoyama, M., Seki, R., Michael, C. A., Yamaguchi, H., Suzuki, C., Shimizu, A., Tokuzawa, T., Yoshinuma, M., Akiyama, T., Ida, K., Yamada, I., Yasuhara, R., Funaba, H., Kobayashi, T., Yamada, H., Du, X. D., Vyacheslavov, L. N., Mikkelsen, D. R., and Yun, G. S.. Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD. United States: N. p., Web. doi:10.1088/1741-4326/aa79c6.
Tanaka, K., Nagaoka, K., Murakami, S., Takahashi, H., Osakabe, M., Yokoyama, M., Seki, R., Michael, C. A., Yamaguchi, H., Suzuki, C., Shimizu, A., Tokuzawa, T., Yoshinuma, M., Akiyama, T., Ida, K., Yamada, I., Yasuhara, R., Funaba, H., Kobayashi, T., Yamada, H., Du, X. D., Vyacheslavov, L. N., Mikkelsen, D. R., & Yun, G. S.. Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD. United States. doi:10.1088/1741-4326/aa79c6.
Tanaka, K., Nagaoka, K., Murakami, S., Takahashi, H., Osakabe, M., Yokoyama, M., Seki, R., Michael, C. A., Yamaguchi, H., Suzuki, C., Shimizu, A., Tokuzawa, T., Yoshinuma, M., Akiyama, T., Ida, K., Yamada, I., Yasuhara, R., Funaba, H., Kobayashi, T., Yamada, H., Du, X. D., Vyacheslavov, L. N., Mikkelsen, D. R., and Yun, G. S.. 2017. "Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD". United States. doi:10.1088/1741-4326/aa79c6. https://www.osti.gov/servlets/purl/1474420.
@article{osti_1474420,
title = {Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD},
author = {Tanaka, K. and Nagaoka, K. and Murakami, S. and Takahashi, H. and Osakabe, M. and Yokoyama, M. and Seki, R. and Michael, C. A. and Yamaguchi, H. and Suzuki, C. and Shimizu, A. and Tokuzawa, T. and Yoshinuma, M. and Akiyama, T. and Ida, K. and Yamada, I. and Yasuhara, R. and Funaba, H. and Kobayashi, T. and Yamada, H. and Du, X. D. and Vyacheslavov, L. N. and Mikkelsen, D. R. and Yun, G. S.},
abstractNote = {Here, surveys of the ion and electron heat transports of neutral beam (NB) heating plasma were carried out by power balance analysis in He and H rich plasma at LHD. Collisionality was scanned by changing density and heating power. The characteristics of the transport vary depending on collisionality. In low collisionality, with low density and high heating power, an ion internal transport barrier (ITB) was formed. The ion heat conductivity (χi) is lower than electron heat conductivity (χe) in the core region at ρ < 0.7. On the other hand, in high collisionality, with high density and low heating power, χi is higher than χe across the entire range of plasma. These different confinement regimes are associated with different fluctuation characteristics. In ion ITB, fluctuation has a peak at ρ = 0.7, and in normal confinement, fluctuation has a peak at ρ = 1.0. The two confinement modes change gradually depending on the collisionality. Scans of concentration ratio between He and H were also performed. The ion confinement improvements were investigated using gyro-Bohm normalization, taking account of the effective mass and charge. The concentration ratio affected the normalized χi only in the edge region (ρ ~ 1.0). This indicates ion species effects vary depending on collisionality. Turbulence was modulated by the fast ion loss instability. The modulation of turbulence is higher in H rich than in He rich plasma.},
doi = {10.1088/1741-4326/aa79c6},
journal = {Nuclear Fusion},
number = 11,
volume = 57,
place = {United States},
year = {2017},
month = {8}
}