2005 Fiscal Year Final Research Report Summary
Study of Self organization of current hole in high confinement plasma
| Project/Area Number |
15340203
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Plasma science
|
|---|
| Research Institution | Japan Atomic Energy Agency |
|---|
Principal Investigator |
OZEKI Takahisa Japan Atomic Energy Agency, Fusion Research and Development Directorate, Senior Principal Researcher, 核融合研究開発部門, 研究主席 (50354577)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
FUJITA Takaaki Japan Atomic Energy Agency, Fusion Research and Development Directorate, Principal Researcher, 核融合研究開発部門, 研究主幹 (70354602)
TAKIZUKA Tomonori Japan Atomic Energy Agency, Fusion Research and Development Directorate, Assistant Principal Researcher, 核融合研究開発部門, 研究副主幹 (40354576)
TUDA Takashi Japan Atomic Energy Agency, Fusion Research and Development Directorate, Principal Researcher, 核融合研究開発部門, 研究職 (10354581)
NAKAMURA Yukiharu Japan Atomic Energy Agency, Fusion Research and Development Directorate, Principal Researcher, 核融合研究開発部門, 研究主幹 (80354570)
HAYASHI Nobuhiko Japan Atomic Energy Agency, Fusion Research and Development Directorate, Researcher, 核融合研究開発部門, 研究職 (10354573)
|
|---|
| Project Period (FY) |
2003 – 2005
|
| Keywords | current hole / tokamak / plasma / self-organization / heat / particle transport / MHD / simulation |
|---|
| Research Abstract |
Purpose of this study is to clarify the mechanism of self-organization of current hole observed in JT-60U large tokamak. The following results are obtained.
1.Tri-magnetic island (ATMI) model is proposed as equilibrium with nearly zero current around the plasma center. The condition of the stable existence of the ATMI model is obtained.
2.MHD stability of plasmas with strongly hollow current profile like the current hole is investigated. Analysis shows that the possibility to obtain the high beta plasma (β_N>4) by tailoring the pressure profile and the current profile such as the pressure gradient exists in the strong reversed shear region.
3.Formation and sustainment of the current hole are investigated by the comparison of simulations of the 1.5 dimension transport code using the ATMI equilibrium model with experimental observations in JT-60U. Results show that both of the formation of strong internal transport barrier (ITB) and the rapid drop of the anomalous transport makes a self-organization of the current hole by the penetration of the negative electric field due to the increase of the local bootstrap current. Also, the energy confinement law within the current hole and the property of the sustainment by using the current drive are clarified.
4.By the MHD simulation, the response to the plasma with negative electric field is investigated, and the formation of the pair vortices is obtained as an explanation of the current hole. The interaction of the pair vortices and the residual magnetic field removes the negative electric field.
The current hole plasma has the strong ITB and the neo-classical level transport near the plasma center, also it has a possibility to become a very high beta by tailoring the pressure and current profiles. Therefore, the tokamak fusion reactor using the current hole has a potential to become an extremely high efficiency reactor.
|
