Gyrokinetic microinstability analysis of high-T i and high-T e isotope plasmas in Large Helical Device

Motoki Nakata; Kenichi Nagaoka; Kenji Tanaka; Hiromi Takahashi; Masanori Nunami; Shinsuke Satake; Masayuki Yokoyama; Felix Warmer

doi:10.1088/1361-6587/aadd6a

Gyrokinetic microinstability analysis of high-T _i and high-T _e isotope plasmas in Large Helical Device

Motoki Nakata (Corresponding author), Kenichi Nagaoka, Kenji Tanaka, Hiromi Takahashi, Masanori Nunami, Shinsuke Satake, Masayuki Yokoyama, Felix Warmer

Research output: Contribution to journal › Article › Academic › peer-review

22 Citations (Scopus)

Abstract

Transport and confinement characteristics, and microinstabilities for high- and high- isotope plasmas in Large Helical Device are explored by using the gyrokinetic Vlasov simulation GKV with hydrogen isotope ions and real-mass kinetic electrons. The experimental data indicate that the thermal diffusivity is reduced in the deuterium-dominated plasmas, where the deviation from the gyro-Bohm scaling in the overall tendency and the strong anomaly of the electron heat transport are identified. Linear gyrokinetic analyses identify that the growth rates of the ion temperature gradient and trapped electron mode (TEM) instabilities in the deuterium plasmas are reduced due to the change in the profile gradients and/or the isotope ion mass, and the radial dependence of the mixing-length diffusivity is qualitatively consistent with the experimental tendency. Also, TEM-like turbulent fluctuations are examined by the using the phase contrast imaging measurement and the linear gyrokinetic calculation for the high- deuterium plasma.

Original language	English
Article number	014016
Number of pages	7
Journal	Plasma Physics and Controlled Fusion
Volume	61
Issue number	1
DOIs	https://doi.org/10.1088/1361-6587/aadd6a
Publication status	Published - Jan 2019
Externally published	Yes

Bibliographical note

Funding Information:
The authors would like to thank Drs H Sugama, T-H Wata-nabe, S Toda, H Yamaguchi, and C Hidalgo for fruitful discussions on this study. Numerical simulations were performed by Plasma Simulator at NIFS, and by FX100 at Nagoya University. This work is supported by the MEXT Japan, Grant No. 17K14899, in part by the NIFS collaborative Research Programs, and in part by the MEXT grant for Post-K project: Development of Innovative Clean Energy, Core Design of Fusion Reactor.

Funding

The authors would like to thank Drs H Sugama, T-H Wata-nabe, S Toda, H Yamaguchi, and C Hidalgo for fruitful discussions on this study. Numerical simulations were performed by Plasma Simulator at NIFS, and by FX100 at Nagoya University. This work is supported by the MEXT Japan, Grant No. 17K14899, in part by the NIFS collaborative Research Programs, and in part by the MEXT grant for Post-K project: Development of Innovative Clean Energy, Core Design of Fusion Reactor.

Keywords

helical plasmas
LHD experiment
microinstability
plasma confinement
plasma turbulence
stellarator plasmas

Access to Document

10.1088/1361-6587/aadd6a

Cite this

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title = "Gyrokinetic microinstability analysis of high-T i and high-T e isotope plasmas in Large Helical Device",

abstract = "Transport and confinement characteristics, and microinstabilities for high- and high- isotope plasmas in Large Helical Device are explored by using the gyrokinetic Vlasov simulation GKV with hydrogen isotope ions and real-mass kinetic electrons. The experimental data indicate that the thermal diffusivity is reduced in the deuterium-dominated plasmas, where the deviation from the gyro-Bohm scaling in the overall tendency and the strong anomaly of the electron heat transport are identified. Linear gyrokinetic analyses identify that the growth rates of the ion temperature gradient and trapped electron mode (TEM) instabilities in the deuterium plasmas are reduced due to the change in the profile gradients and/or the isotope ion mass, and the radial dependence of the mixing-length diffusivity is qualitatively consistent with the experimental tendency. Also, TEM-like turbulent fluctuations are examined by the using the phase contrast imaging measurement and the linear gyrokinetic calculation for the high- deuterium plasma.",

keywords = "helical plasmas, LHD experiment, microinstability, plasma confinement, plasma turbulence, stellarator plasmas",

author = "Motoki Nakata and Kenichi Nagaoka and Kenji Tanaka and Hiromi Takahashi and Masanori Nunami and Shinsuke Satake and Masayuki Yokoyama and Felix Warmer",

note = "Funding Information: The authors would like to thank Drs H Sugama, T-H Wata-nabe, S Toda, H Yamaguchi, and C Hidalgo for fruitful discussions on this study. Numerical simulations were performed by Plasma Simulator at NIFS, and by FX100 at Nagoya University. This work is supported by the MEXT Japan, Grant No. 17K14899, in part by the NIFS collaborative Research Programs, and in part by the MEXT grant for Post-K project: Development of Innovative Clean Energy, Core Design of Fusion Reactor. ",

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T1 - Gyrokinetic microinstability analysis of high-T i and high-T e isotope plasmas in Large Helical Device

AU - Nakata, Motoki

AU - Nagaoka, Kenichi

AU - Tanaka, Kenji

AU - Takahashi, Hiromi

AU - Nunami, Masanori

AU - Satake, Shinsuke

AU - Yokoyama, Masayuki

AU - Warmer, Felix

N1 - Funding Information: The authors would like to thank Drs H Sugama, T-H Wata-nabe, S Toda, H Yamaguchi, and C Hidalgo for fruitful discussions on this study. Numerical simulations were performed by Plasma Simulator at NIFS, and by FX100 at Nagoya University. This work is supported by the MEXT Japan, Grant No. 17K14899, in part by the NIFS collaborative Research Programs, and in part by the MEXT grant for Post-K project: Development of Innovative Clean Energy, Core Design of Fusion Reactor.

PY - 2019/1

Y1 - 2019/1

N2 - Transport and confinement characteristics, and microinstabilities for high- and high- isotope plasmas in Large Helical Device are explored by using the gyrokinetic Vlasov simulation GKV with hydrogen isotope ions and real-mass kinetic electrons. The experimental data indicate that the thermal diffusivity is reduced in the deuterium-dominated plasmas, where the deviation from the gyro-Bohm scaling in the overall tendency and the strong anomaly of the electron heat transport are identified. Linear gyrokinetic analyses identify that the growth rates of the ion temperature gradient and trapped electron mode (TEM) instabilities in the deuterium plasmas are reduced due to the change in the profile gradients and/or the isotope ion mass, and the radial dependence of the mixing-length diffusivity is qualitatively consistent with the experimental tendency. Also, TEM-like turbulent fluctuations are examined by the using the phase contrast imaging measurement and the linear gyrokinetic calculation for the high- deuterium plasma.

AB - Transport and confinement characteristics, and microinstabilities for high- and high- isotope plasmas in Large Helical Device are explored by using the gyrokinetic Vlasov simulation GKV with hydrogen isotope ions and real-mass kinetic electrons. The experimental data indicate that the thermal diffusivity is reduced in the deuterium-dominated plasmas, where the deviation from the gyro-Bohm scaling in the overall tendency and the strong anomaly of the electron heat transport are identified. Linear gyrokinetic analyses identify that the growth rates of the ion temperature gradient and trapped electron mode (TEM) instabilities in the deuterium plasmas are reduced due to the change in the profile gradients and/or the isotope ion mass, and the radial dependence of the mixing-length diffusivity is qualitatively consistent with the experimental tendency. Also, TEM-like turbulent fluctuations are examined by the using the phase contrast imaging measurement and the linear gyrokinetic calculation for the high- deuterium plasma.

KW - helical plasmas

KW - LHD experiment

KW - microinstability

KW - plasma confinement

KW - plasma turbulence

KW - stellarator plasmas

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