Effect of magnetic well on the formation of edge transport barrier

• Project/Area Number: 16360462
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: National Institute for Fusion Science
• Principal Investigator: OKAMURA Shoichi National Institute for Fusion Science, LHD department, Professor (60115540)
• Co-Investigator(Kenkyū-buntansha): ISOBE Mitsutaka National Institute of Fusion Science, LHD department, Research associate (00300731) ; FUJISAWA Akihide National Institute of Fusion Science, LHD department, Assistant Professor (60222262) ; MATSUO Keiji Fukuoka Institute of Technology, Engineering department, Professor (10199755) ; IGUCHI Harukazu National Institute of Fusion Science, LHD department, Assistant Professor (40115522) ; MATSUOKA Keisuke National Institute of Fusion Science, LHD department, Professor (70023736)
• Project Period (FY): 2004 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥4,600,000 (Direct Cost: ¥4,600,000); Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2004: ¥2,700,000 (Direct Cost: ¥2,700,000)
• Keywords: Edge transport barrier / H-mode / Magnetic axis shift / Magnetic well / Zonal flow / Fluctuation measurement / 揺動測定 / ゾーナルフロー / ETB / 周辺部輸送障壁 / Transport Barrier / 磁気丘

Research Abstract

Objectives of this research program are 1) to study the relation between the magnetic well configuration and the confinement improvement with the edge transport barrier (ETB) formation, and 2) to investigate the changes of amplitude and spectrum of plasma turbulence due to the ETB formation. Advanced diagnostic technologies were fully utilized for the turbulence measurements with the ETB formation. Zonal flows were identified by a heavy ion beam probe (HIBP) measurements which was the first demonstration of the existence of such a meso-scale structural formation in the toroidal magnetic confinement experiments. The reduction of plasma fluctuations was shown in the beam emission spectroscopy (BES) measurements with the formation of ETB and the profile data of the fluctuations exhibited the strong suppression of them at the normalized minor radius 0.95. The fluctuation measurements using Langmuir probes also showed the existence of the transport barrier at this minor radius. The reduction of the fluctuations with the ETB formation was confirmed by two other density fluctuation diagnostic a phase contrast method with YAG laser and the microwave scattering diagnostics. A carbon limiter was prepared for the experiment to compare the magnetic configurations with magnetic hill region and the one with magnetic well. The limiter was used to cut off the magnetic hill part at the plasma edge. In order to obtain good discharge condition, a conditioning of the carbon limiter was intensively made because the control of the neutral gas pressure at the plasma edge is very important for the ETB formation. At the final phase of the program, the conditioning of the carbon head was not sufficient for getting the clear results in the comparison of two magnetic configurations in the ETB formation.

Research Products

• [Journal Article] Improved Confinement and Related Physics Study in the Compact Helical System (2007)
  • Author(s): S.Okamura, et. al.
  • Journal Title: Fusion Science and Technology 51 Pages: 46-53
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] 'Improved confinement and related physics study in the Compact Helical System' (2007)
  • Author(s): S. Okamura, T. Akiyama, A. Fujisawa, K. Ida, H. Iguchi, M. Isobe, S. Kado, T. Minami, K. Nagaoka, K. Nakamura, S. Nishimura, K. Matsuoka, H. Matsushita, H. Nakano, S. Ohshima, T. Oishi, A. Shimizu, C. Suzuki, C. Takahashi, K. Toi, Y. Yoshimura, M. Yoshinuma, CHS group
  • Journal Title: Fusion Science and Technology Vol.51 Pages: 46-53
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Improved Confinement and Related Physics Study in the Compact Helical System (2007)
  • Author(s): S.Okamura
  • Journal Title: Fusion Science and Technology 51, no.1 Pages: 46-53
• [Journal Article] Progress of Confinement Physics Study in Compact Helical System (2007)
  • Author(s): S.Okamura
  • Journal Title: Proceedings of 21st IAEA Fusion Energy Conference (CD ROM)
• [Journal Article] Plasma-Confinement Physics Study in Compact Helical System (2006)
  • Author(s): S.Okamura, et. al.
  • Journal Title: Journal of the Korean Physical Society 49
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] 'Scaling of power threshold for edge transport barrier formation in CHS with density, magnetic field and magnetic configuration' (2006)
  • Author(s): T Akiyama, S Okamura, T Minami, A Fujisawa, T Oishi, S Kado, M Takeuchi, K Toi, K Ida, M Yoshinuma, K Matsuoka, M Isobe, S Nishimura, C Suzuki, Y Yoshimura, K Nagaoka, C Takahashi, the CHS Experimental Group
  • Journal Title: Plasma Physics and Controlled Fusion Vol.48 Pages: 1683-1692
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] 'Plasma-confinement physics study in Compact Helical System' (2006)
  • Author(s): S. Okamura, T. Akiyama, A. Fujisawa, K. Ida, H. Iguchi, R. Ikeda, M. Isobe, Y. Jinguji, T. Kobuchi, K. Matsuoka, H. Matsushita, T. Minami, S. Mizuno, K. Nagaoka, K. Nakamura, H. Nakano, S. Nishimura, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, M. Takeuchi, K. Toi, Y. Yoshimura, M. Yoshinuma, S. Kado, K. Matsuo, T. Oishi
  • Journal Title: Journal of Korean Physical Society Vol.49
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Plasma-Confinement Physics Study in Compact Helical System (2006)
  • Author(s): S.Okamura
  • Journal Title: Journal of the Korean Physical Society 49, Suppl
• [Journal Article] Spectrograph of electric field fluctuation in toroidal helical plasma (2006)
  • Author(s): A.Fujisawa
  • Journal Title: Plasma Physics and Controlled Fusion 48, no.4
• [Journal Article] Edge and internal transport barrier formation in CHS (2005)
  • Author(s): S.Okamura, et. al.
  • Journal Title: Nuclear Fusion 45 Pages: 863-870
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] 'Edge and internal transform barrier formation in CHS' (2005)
  • Author(s): S. Okamura, T. Minamai, T. Akiyama, T. Oishi, A. Fujisawa, K. Ida, H. Iguchi, M. Isobe, S. Kado, K. Nagaoka, K. Nakamura, S. Nishimura, K. Matsuoka, H. Matsushita, H. Nakano, M. Nishiura, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, K. Toi, Y. Yoshimura, M. Yoshinuma, CHS group
  • Journal Title: Nuclear Fusion Vol.45 Pages: 863-870
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Edge and internal transport barrier formation in CHS (2005)
  • Author(s): S.Okamura
  • Journal Title: Nuclear Fusion 45, no.8 Pages: 863-870
• [Journal Article] Improved confinement and related physics study in Compact Helical System (2005)
  • Author(s): S.Okamura
  • Journal Title: Proceedings of International Stellarator Workshop (CD-ROM)
• [Journal Article] Two-dimensional diagnostic of edge plasma structure using a lithium beamprobe in a compact helical system (2005)
  • Author(s): K.Nakamura
  • Journal Title: Review of Scientific Instruments 76, no.1 Pages: 13504-13504
• [Journal Article] Identification of Zonal Flow in a Toroidal Plasma' (2004)
  • Author(s): A. Fujisawa, K. Itoh, H. Iguchi, K. Matsuoka, S. Okamura, A. Shimizu, T. Minami, Y. Yoshimura, K. Nagaoka, C. Takahashi, M. Kojima, H. Nakano, S. Ohsima, S. Nishimura, M. Isobe, C. Suzuki, T. Akiyama, K. Ida, K. Toi, S.-I. Itoh, P. H., Diamond
  • Journal Title: Physical Review Letters Vol.93
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Confinement characteristics of the quasi-axisymmetric stellarator CHS-qa (2004)
  • Author(s): S.Okamura
  • Journal Title: Nuclear Fusion 44, no.4 Pages: 575-581
• [Journal Article] Edge Transport barrier formation in compact helical system (2004)
  • Author(s): S.Okamura
  • Journal Title: Plasma Physics and Controlled Fusion 46, no.5
• [Journal Article] Edge and Internal Transport Barrier Formations in CHS (2004)
  • Author(s): S.Okamura
  • Journal Title: Proceedings of Fusion Energy Conference 2004 (CD ROM)
• [Journal Article] Identification of Zonal Flows in a Toroidal Plasma (2004)
  • Author(s): A.Fujisawa
  • Journal Title: Physical Review Letters 93, no.16
• [Presentation] CHS group, Edge and Internal Transport Barrier Formations in CHS (2007)
  • Author(s): S. Okamura, T. Minami, T. Akiyama, T. Oishi, A. Fujisawa, K. Ida, H. Iguchi, M. Isobe, S. Kado, K. Nagaoka, K. Nakamura, S. Nishimura, K. Matsuoka, H. Matsushita, H. Nakano, M. Nishiura, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, K. Toi, Y. Yoshimura, M. Yoshinuma
  • Organizer: 20th IAEA Fusion Energy Conference
  • Place of Presentation: Vilamoura(Portugal)
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Summary of H-mode studies in Compact Helical System (2007)
  • Author(s): S. Okamura, T. Minami, T. Akiyama, A. Fujisawa, K. Ida, H. Iguchi, R. Ikeda, M. Isobe, S. Kadoa, K. Matsuob, K. Matsuoka, K. Nagaoka, K. Nakamura, H. Nakano, S. Nishimura, T. Oishi, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, M. Takeuchi, K. Toi, N. Tomitac, S. Tsuji-Iioc, Y. Yoshimura, M. Yoshinuma, CHS group
  • Organizer: Intenational Stellarator/Heliotron Workshop
  • Place of Presentation: Toki(Japan)
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Progress of Confinement Physics Study in Compact Helical System (2006)
  • Author(s): S.Okamura, et. al.
  • Organizer: 21st IAEA Fusion Energy Conference
  • Place of Presentation: 成都(中国)
  • Year and Date: 2006-10-19
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Plasma Confinement Physics Study in Compact Helical System (2006)
  • Author(s): S. Okamura, T. Akiyama, A. Fujisawa, K. Ida, H. Iguchi, R. Ikeda, M. Isobe, Y. Jinguji, S. Kado, T. Kobuchi, K. Matsuo, K. Matsuoka, H. Matsushita, T. Minami, S. Mizuno, K. Nagaoka, K. Nakamura, H. Nakano, S. Nishimura, T. Oishi, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, M. Takeuchi, K. Toi, Y. Yoshimura, M. Yoshinuma
  • Organizer: 21st IAEA Fusion Energy Conference
  • Place of Presentation: Chendu(Chine)
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Plasma Confinement Physics Study in Compact Helical System (2005)
  • Author(s): S. Okamura, T. Akiyama, A. Fujisawa, K. Ida, H. Iguchi, R. Ikeda, M. Isobe, Y. Jinguji, S. Kado, T. Kobuchi, K. Matsuo, K. Matsuoka, H. Matsushita, T. Minami, S. Mizuno, K. Nagaoka, K. Nakamura, H. Nakano, S. Nishimura, T. Oishi, S. Ohshima, A. Shimizu, C. Suzuki, C. Takahashi, M. Takeuchi, K. Toi, Y. Yoshimura and M. Yoshinuma
  • Organizer: 5th General Scientific Assembly of the Asia Plasma and Fusion Association
  • Place of Presentation: Jeju island(Korea)
  • Description: 「研究成果報告書概要(欧文)」より