Intermittent events dominated by meso-scale physics and control of a macro system in steady state spherical tokamak
Project/Area Number |
21246139
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Research Category |
Grant-in-Aid for Scientific Research (A)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Nuclear fusion studies
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Research Institution | Kyushu University |
Principal Investigator |
ZUSHI Hideki 九州大学, 応用力学研究所, 教授 (20127096)
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Co-Investigator(Kenkyū-buntansha) |
SHIKAMA Taiichi 京都大学, 工学研究科, 講師 (80456152)
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Project Period (FY) |
2009 – 2012
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Project Status |
Completed (Fiscal Year 2012)
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Budget Amount *help |
¥43,550,000 (Direct Cost: ¥33,500,000、Indirect Cost: ¥10,050,000)
Fiscal Year 2012: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2011: ¥11,310,000 (Direct Cost: ¥8,700,000、Indirect Cost: ¥2,610,000)
Fiscal Year 2010: ¥13,260,000 (Direct Cost: ¥10,200,000、Indirect Cost: ¥3,060,000)
Fiscal Year 2009: ¥14,690,000 (Direct Cost: ¥11,300,000、Indirect Cost: ¥3,390,000)
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Keywords | メゾスケール / blob / fast camera / PDP |
Research Abstract |
This research is aiming at the subject associated with "Intermittent events dominated by meso-scale physics and control of a macro system in steady state spherical tokamak". Mainly, structure formation and its controllability under a process from an open magnetic field configuration to the closed one, contact to two closed magnetic surfaces, and open field region outside the closed one are of interest.During the research period, 1) current start-up in tokamak using non-inductive method and 2) blob propagation crossing the SOL region, which extends from the closed flux surfaces to the open ones. These phenomena can be recognized as intermitted or off-normal events against the steady state operation of the tokamak plasma. This research aims at pointing out the characteristics of the meso-scale physics for the macroscopic structure formation under the microscopic turbulence. The evaluation for the coupling coefficient between the meso-scopic and macroscopic systems will be investigated by
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evaluation of a phase relaxation time. Finally we would like to establish control methods for steady state tokamak operation. During H21-23 experiments for rf driven non-inductive plasma production and sustainment have been performed in QUEST and CPD. The followings have been achieved. (1) Using 8.2 GHz ECWs at ~ 100 kW, non-inductive current start-up and current sustainment has been successfully demonstrated at 35 kA, which is the world record. High poloidal equilibrium at ・・p =1.5 and ・<1(triangles) has been obtained. The maximum duration of 300 sec is also performed for ST configuration. During the formation phase from the open to closed surfaces, several diagnostic tools have been applied and then the following physical picture could be drawn. The chamber aspect ratio is small enough for several harmonics to exist inside the plasma, and it has been found that the MOMFC(mirror ratio depending on the Bzcurvature) and the amplitude of Bz/Bt contribute to the fast ramp-up of the current, because ofthe initially born energetic electrons of 10 keV could be well confined in the open magnetic fields. The high ・・p~ 1 plasma scenario has been demonstrated at high MOMFC=2 and Bz/Btof 10 %. Ipof 16 kA at the high current ramp-up rate of 0.3 - 0.5 MA/s was achieved non-inductively. A natural inboard poloidal field null appeared as MOMFCincreased and this equilibrium could be sustained for ~ 10 seconds. Based on the fluctuation measurements it has been observed that the long correlation length along the magnetic surfaces has been measured when a closed surface is formed. Thisindicates that the phenomenon dominated by a mesoscopic scale occurred during the topological change. (2)The second aspect addressed in this research isthe statistical approach of the SOL turbulence, plasma transport, blob propagation.This is aimed at identification ofthe generation region of the blob by charactering the pdf of the fluctuations, two dimensional structure of pdf and statistical aspect, blob propagation and acceleration, and flow pattern in the SOL and its impact on the turbulent transport. These observations have been carried out by using the wide viewing fast camera imaging and local probe measurements. Statistical aspects of the convective transport with respect to the variation in magnetic field pitch are dwelled upon. Progressive enhancement of fluctuations and consequent blob generation and propagation are observed with the increase in Bzat a constant Bt. Amplitude and waiting time of the blobs attains a maximum for highest Bz/Bt(=7.8%). 2D statistical analysis of the images enables us to identify blobformation location precisely at the steep density gradient region. Accelerated radial propagation was observed for large sized blobs. The effect of mirror ratio on turbulence is studied with the change in poloidal field curvature. Fluctuation characteristics are quite different for magnetic shears. The region characterized by the deviation of pdf from the Gaussian to gamma can be considered as a typical scale, with which the mesoscopic phenomenon dominates. A new diagnostic and analytical method have been developed to evaluate the plasma flow using the fluctuations. Less
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Report
(4 results)
Research Products
(95 results)
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[Journal Article] Statistical Interpretation of the Density Fluctuations From the High-Speed Visible Images of Edge Turbulence on QUEST2011
Author(s)
Santanu Banerjee, H.Zushi, N.Nishino, K.Hanada, H.Q.Liu, M.Ishiguro, T.Ryoukai, S.Tashima, K.Nakamura, H.Idei, M.Hasegawa, A.Fujisawa, the QUEST group
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Journal Title
IEEE TRANSACTIONS ON PLASMA SCIENCE
Volume: VOL.39, NO.11
Pages: 3006-3007
Related Report
Peer Reviewed
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[Journal Article] Measurement of hydrogen permeation due to atmic flux using permeation probe in the spherical tokamak QUEST2010
Author(s)
SanjieevK Sharma, Hideki Zushi, Ikuji Takagi, Yuki Hisano, Mizuki Aakamoto, Yuta Higashizono, Taichi Shikama, Sigeru Morita, Tetsuo Tanabe, Naoaki Yoshida, Kazuaki Hanada, Makoto Hasegawa, Osamu Mitarai, Kazuo Nakamura, Hiroshi Idei, Kohnosuke N Sato, Shoji Kawasaki, Hisatoshi Nakashima, Aki Higashijima, Yousuke Nakashima, Nobuyuki Nishino, Yuji Hatano, Akira Sagara, Yukio Nakamura, Naoka Ashikawa, Takashi Maekawa
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Journal Title
Fusion Engineering and Design
Volume: 85
Pages: 950-955
Related Report
Peer Reviewed
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[Journal Article] Analysis of the footprint traces on first walls of the compact plasma wall interaction device CPD using surface analysis and electron orbit calculations2010
Author(s)
S.K.Sharma, H.Zushi, M.Osakabe, Y.Takeiri, N.Yoshida, M.Hasegawa, T.Yoshinaga, K.Hanada, H.Idei, M.Sakamoto, K.Nakamura, K.N.Sato, CPD Group
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Journal Title
Nuclear Fusion
Volume: 50
Related Report
Peer Reviewed
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[Presentation] QUEST電流駆動における自発的内側poloidal field null配位の形成について2012
Author(s)
H.Zushi, S.Tashima, M.Ishiguro, M.Hasegawa, S.Barnejee, H.Nishino, M.Isobe, K.Hanada, H.Idei, K.Nakamura, A.Fujisawa, Y.Nagashima, K.Matsuoka, K.Toi, T.Maekawa, Y.Takase, M.Kikuchi, A.Fukuyama, A.Ejiri, Y.Ueda, O.Mitarai, S.Okamura
Organizer
日本物理学会第67回年次大会
Place of Presentation
関西学院大学
Year and Date
2012-03-26
Related Report
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[Presentation] QUEST装置における硬X線計測によるECH電流立ち上げ時と定常維持時の高速電子解析2012
Author(s)
田島西夜, 図子秀樹, 磯部光孝, 岡村昇一, 出射浩, 花田和明, 中村一男, 藤澤彰英, 長谷川真, 永島芳彦, 石黒正貴, 川崎昌二, 中島寿年, 東島亜紀
Organizer
日本物理学会第67回年次大会
Place of Presentation
関西学院大学
Year and Date
2012-03-26
Related Report
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[Presentation] Effect of poloidal magnetic field topology on the edge turbulence of 8.2 GHz slab plasma in QUEST2012
Author(s)
Santanu Banerjee, H.Zushi, N.Nishino, K.Hanada, H.Honma, H.Q.Liu, M.Ishiguro, T.Ryoukai, S.Tashima, T.Inoue, K.Nakamura, H.Idei, M.Hasegawa, A.Fujisawa, K.Matsuoka, the QUEST group
Organizer
日本物理学会第67回年次大会
Place of Presentation
関西学院大学
Year and Date
2012-03-25
Related Report
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[Presentation] He分光イメージングを用いた周辺プラズマ電子密度・温度計測2011
Author(s)
井上翼, 図子秀樹, 西野信博, 了戒智文, Santanu Banerjee, 長谷川真, 中村一男, 花田和明, 藤澤彰英, 出射浩, 永島芳彦, 川崎昌二, 中島寿年, 東島亜紀
Organizer
プラズマ核融合九州山口沖縄支部大会
Place of Presentation
大分大学
Year and Date
2011-12-17
Related Report
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[Presentation] ECW/EBW Heating and Current Drive Experi ment Results and Prospects to CW Operation in QUEST2011
Author(s)
H.Idei, H.Zushi, K.Hanada, K.Nakamura, A.Fujisawa, M.Hasegawa, N.Yoshida, M.Sakamoto, H.Watanebe, K.Tokunaga, Y.Nagashima, A.Ejiri, M.Sakaguchi, E.Kalinnikova, M.Ishiguro, S.Tashima, A.Fukuyama H.Igami, S.Kubo, S.K.Sharma, T.Ryokai, H.Q.Liu, M.Isobe, K.Nagaoka, H.Nakanishi, N.Nishino, S.Kawasaki, H.Nakashima A.Higashijima, Y.Takase, T.Maekawa, O.Mitarai, M.Kikuchi, K.Toi
Organizer
21st International Toki Conference (ITC-21)
Place of Presentation
Ceratopia Toki, Toki-City, Gifu, Japan
Year and Date
2011-11-29
Related Report
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[Presentation] Statistical analysis of the convective intermittent transport at the edge region of QUEST2011
Author(s)
Santanu Banerjee, H.Zushi, N.Nishino, K.Hanada, S.K.Sharma, T.Inoue, H.Honma, H.Q.Liu, M.Ishiguro, T.Ryoukai, S.Tashima, K.Nakamura, H.Idei, M.Hasegawa, A.Fujisawa, the QUEST group
Organizer
The Joint Meeting of 5th IAEA Technical Meeting on Spherical Tori 16th International Workshop on Spherical Torus (ISTW2011) 2011 US-Japan Workshop on ST Plasma
Place of Presentation
National Institute for Fusi on Science, Toki, Japan
Year and Date
2011-09-28
Related Report
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[Presentation] QUEST experiments towards steady state operation of spherical tokamaks2011
Author(s)
K.Hanada, H.Zushi, H.Idei, K.Nakamura, M.Ishiguro, S.Tashima, E.I.Kalinnikova, M.Sakamoto, M.Hasegawa, A.Fujisawa, K.N.Sato, N.Yoshid, H.Watanab, K.Tokunaga, Y.Nagashima, A.Higashijima, S.Kawasaki, H.Nakashima, H.Liu, O.Mitarai, T.Maekawa, A.Fukuyama, Y.Takase, J.Qian
Organizer
The Joint Meeting of 5th IAEA Technical Meeting on Spherical Tori 16th International Workshop on Spherical Torus (ISTW2011) 2011 US-Japan Workshop on ST Plasma
Place of Presentation
National Institute for Fusi on Science, Toki, Japan
Year and Date
2011-09-27
Related Report
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[Presentation] Origin and evolution of coherent convective structures investigated using fast imaging in QUEST2011
Author(s)
Santanu Banerjee, H.Zushi, N.Nishino, K.Hanada, H.Honma, H.Q.Liu, M.Ishiguro, T.Ryoukai, S.Tashima, K.Nakamura, H.Idei, M.Hasegawa, A.Fujisawa, the QUEST group
Organizer
1st Asia Pacific Transport Working Group (APTWG)
Place of Presentation
National Institute for Fusi on Science, Toki, Japan
Year and Date
2011-06-15
Related Report
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[Presentation] Hydrogen Permeation Measurements in the Spherical Tokamak QUEST and its Numerical Modeling2010
Author(s)
S.K.Sharma, H.Zushi, I.Takagi, Y.Hisano, T.Shikama, S.Morita, T.Tanabe, N.Yoshida, M.Sakamoto, Y.Higashizono, K.Hanada, M.Hasegawa, O.Mitarai, K.Nakamura, H.Idei, K.N.Sato, S.Kawasaki, H.Nakashima, A.Higashijima, Y.Nakashima, N.Nishino, Y.Hatano, A.Sagara, Y.Nakamura, N.Ashikawa, T.Maekawa, Y.Kishimoto, Y.Takase, QUEST Group
Organizer
The 9th International Conference on Tritium Science and Technology (TRITIUM 2010)
Place of Presentation
Nara
Year and Date
2010-10-25
Related Report
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[Presentation] The role of fast electrons on the non-inductive current ramp-up in QUEST2010
Author(s)
S.Tashima, H.Zushi, M.Isobe, S.Okamura, H.Idei, K.Hanada, S.K.Sharma, T.Ryoukai, M.Ishiguro, H.Liu, the QUEST group
Organizer
37th EPS Conference on Plasma Physics
Place of Presentation
Dublin
Year and Date
2010-06-25
Related Report
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[Presentation] Wall pumping studies in spherical tokamak QUEST using permeation measurements and a static gas balance method2010
Author(s)
S.K.Sharma, H.Zushi, I.Takagi, Y.Hisano, T.Shikama, S.Morita, T.Tanabe, N.Yoshida, M.Sakamoto, Y.Higashizono, K.Hanada, M.Hasegawa, O.Mitarai, K.Nakamura, H.Idei, K.N.Sato, S.Kawasaki, H.Nakashima, A.Higashijima, Y.Nakashima, N.Nishino, Y.Hatano, A.Sagara, Y.Nakamura, N.Ashikawa, T.Maekawa, Y.Kishimoto, Y.Tasase, QUEST group
Organizer
19th International Conference on Plasma Surface Interactions
Place of Presentation
San Diego, U.S.A
Related Report
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[Presentation] Acceleration of Blob driven by Helcal Instability In a Simple Magnetic Configuration in QUEST2010
Author(s)
H.Zushi, N.Nishino, K.Hanada, H.Honma, H.Q.Liu Y.Higashizono, M Sakamoto, Ogata, S.Tashima, T.Ryoukai, QUEST group
Organizer
19th International Conference on Plasma Surface Interactions
Place of Presentation
San Diego, U.S.A
Related Report
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[Presentation] Hydrogen Permeation and Recombination in Ni Membrane Place on Spherical Tokamak QUEST2010
Author(s)
I.Takagi, H.Zushi, R.Imade, T.Komura, S.K.Sharma, Y.Hisano, Y.Hatano, Y.Nakamura, A.Sagara, N.Ashikawa
Organizer
19th International Conference on Plasma Surface Interactions
Place of Presentation
San Diego, U.S.A
Related Report
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