2005 Fiscal Year Final Research Report Summary
Studies of structure and dynamics of toroidal plasma using twin heavy ion beam probes
| Project/Area Number |
15360497
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | National Institute for Fusion Science |
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Principal Investigator |
FUJISAWA Akihide National Institute for Fusion Science, Large Helical Device Division, Associate Professor, 大型ヘリカル研究部, 助教授 (60222262)
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| Co-Investigator(Kenkyū-buntansha) |
IGUCHI Harukazu National Institute for Fusion Science, Large Helical Device Division, Associate Professor, 大型ヘリカル研究部, 助教授 (40115522)
IDO Takeshi National Institute for Fusion Science, Large Helical Device Division, Research Associate, 大型ヘリカル研究部, 助手 (50332185)
SHIMIZU Akihiro National Institute for Fusion Science, Large Helical Device Division, Research Associate, 大型ヘリカル研究部, 助手 (00390633)
ITOH Kimitaka National Institute for Fusion Science, Large Helical Device Division, Professor, 大型ヘリカル研究部, 教授 (50176327)
SANUKI Heiji National Institute for Fusion Science, Large Helical Device Division, Professor, 大型ヘリカル研究部, 教授 (80109355)
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| Project Period (FY) |
2003 – 2005
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| Keywords | zonal flows / turbulence / heavy ion beam probe / electric field / nonlinear coupling / toroidal plasma / bifurcation / CHS |
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| Research Abstract |
Since 1982 when H-mode was discovered, a number of structures caused by bifurcation in turbulence transport have been found in toroidal plasma The researchover twenty years has shown that electric field shear can reduce the turbulence and resultant transport to form the local transport barrier and cause the bifurcated structures.
Recent simulation and theories expect that the plasma turbulence can generate macroscopic flow through Reynolds stress, and the interaction between macro-scale flow and micro-scale turbulence can affect the saturation level of turbulence and the resultant transport. This is ascribed to the following reasons ; (1)a quasi-energy conservation law is valid for the relation between zonal flow to cause no cross-field transport and turbulence, (2)the time-dependent shear structure of zonal flow also reduces the turbulence. In CHS, using twin heavy ion beam probes constructed with help of this grant-in-aid, the existence of zonal flow was proven in 2004. This is the first achievement in the world. Further more, in 2005 the experiment to prove the nonlinear linkage between zonal flow and turbulence was performed. The experiment successfully verified the existence of such nonlinear interaction between zonal flow and turbulence. In other words, the quasi-energy conservation law was proven using the efficient use of the twin heavy ion beam probes.
The phenomena of zonal flow are ubiquitous in nature. The example includes Jovian belt and zones, terrestrial jet stream, solar tacocline and so on. The achievement of this project should give deep insight to the turbulence phenomena widely observed in the universe.
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