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Journal Articles

Application of the two-dimensional Newcomb problem to compute the stability matrix of external MHD modes in a tokamak

Aiba, Nobuyuki*; Tokuda, Shinji; Ishizawa, Tomoko*; Okamoto, Masao*

Plasma Physics and Controlled Fusion, 46(11), p.1699 - 1721, 2004/11

https://doi.org/10.1088/0741-3335/46/11/003

Times Cited Count：3 Percentile：9.95(Physics, Fluids & Plasmas)

The theory of the Newcomb equation has been applied to low-n external modes in a tokamak and a method has been developed to compute the stability matrix that gives the change of plasma potential energy due to external modes in terms of the surface values of the perturbations. By using this method, the spectral properties of the ideal external modes has been elucidated, such as coupling between external modes and internal modes, and the difference of the stability properties between a normal shear tokamak and a reversed shear tokamak. These results will be also useful in the stability analysis of resistive wall modes.

Journal Articles

Advanced control scenario of high-performance steady-state operation for JT-60 superconducting tokamak

Tamai, Hiroshi; Kurita, Genichi; Matsukawa, Makoto; Urata, Kazuhiro*; Sakurai, Shinji; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Miura, Yushi; Kizu, Kaname; Kamada, Yutaka; et al.

Plasma Science and Technology, 6(3), p.2281 - 2285, 2004/06

https://doi.org/10.1088/1009-0630/6/3/003

Times Cited Count：0 Percentile：0.02(Physics, Fluids & Plasmas)

High performance steady-state operation for JT-60SC are evaluated by the TOPICS analysis. 5 and bootstrap current fraction 86% is kept steady at I=1.5 MA, B=2 T by neutral beam power of 11 MW. The ERATO-J analysis shows that the external-kink mode with multiple toroidal mode numbers of n=1 and n=2 is stable at 5.5 at the average ratio of conducting wall radius to plasma minor radius of about 1.2 with the wall stabilisation effect. Resistive wall modes, induced by a close location of the wall to plasma, is expected to be suppressed by the active feedback stabilisation with a set of non-axisymmetric field coils behind the stabilising plates. Further optimisation for the high- accessibility by the plasma shaping is performed with the TOSCA analysis. The plasma shaping factor defined as S=(I/aB)q and strongly correlated to the plasma elongation and triangularity, is scanned from 4 to 6, which extends the availability of current and pressure profile control for the high performance plasma operation.

Journal Articles

Theory of the Newcomb equation and applications to MHD stability analysis of a tokamak

Tokuda, Shinji; Aiba, Nobuyuki*

Journal of Plasma and Fusion Research SERIES, Vol.6, p.207 - 209, 2004/00

Recent progress in the theory of the Newcomb equation is reported. Emphasis is put on the analysis of external modes including peeling modes (high kink modes), where is the toroidal mode number. A theory for low external modes is developed so that it is also useful for the analysis of resistive wall modes.

Journal Articles

Tokamak MHD stability; Newcomb equation and boundary layer equations

Tokuda, Shinji

Theory of Fusion Plasmas, p.87 - 102, 2002/00

We report on recent development of solution methods of the Newcomb equation and boundary layer equations, which play important roles in MHD stability analysis of a tokamak. Especially, the two-dimensional Newcomb equation is applied to external modes and the method is desctribed for computing the stability matrix of the external modes.

JAEA Reports