Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Aiba, Nobuyuki; Tokuda, Shinji; Ishizawa, Tomoko*
Journal of Plasma Physics, 72(6), p.1127 - 1131, 2006/12
Times Cited Count：1 Percentile：3.54(Physics, Fluids & Plasmas)We develop the method for the stability analysis of a ideal external magnetohydrodynamic (MHD) mode by solving the eigenvalue problem associated with the two-dimensional Newcomb equation, the inertia free linear ideal MHD equation. This eigenvalue problem can be expected to provide a powerful tool for not only a low-n external MHD mode but also a high-n mode, where n is a toroidal mode number. With this method, we analyze an effect of the aspect ratio on the stability of middle-n (1
n10) external MHD modes in tokamaks; this gets attention for the design research of a high performance tokamak. As the result of this work, we study that external MHD modes become stable as the aspect ratio decreases, and also find that the stability of middle-n external modes becomes important because an effect of a conducting wall is enhanced by reducing the aspect ratio.
Aiba, Nobuyuki; Tokuda, Shinji; Ishizawa, Tomoko*; Okamoto, Masao*
Computer Physics Communications, 175(4), p.269 - 289, 2006/08
Times Cited Count：42 Percentile：83.84(Computer Science, Interdisciplinary Applications)The formulation for solving numerically the two-dimensional Newcomb equation has been extended to calculate the vacuum energy integral by using a vector potential method. According to this extention, a stability code MARG2D has been adapted, and coded for parallel computing in order to reduce substantially the CPU time. The MARG2D code enables a fast stability analysis of ideal external MHD modes from low to high toroidal mode numbers on the basis of the single physical model, and then the code works as a powerful tool in an integrated simulation where it is combined with transport codes, and also in the analysis of tokamak edge plasma experiments.
Aiba, Nobuyuki*; Tokuda, Shinji; Ishizawa, Tomoko*; Okamoto, Masao*
Plasma Physics and Controlled Fusion, 46(11), p.1699 - 1721, 2004/11
Times Cited Count：3 Percentile：9.99(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.
Aiba, Nobuyuki; Tokuda, Shinji; Ishizawa, Tomoko*; Ozeki, Takahisa
no journal, ,
no abstracts in English
Aiba, Nobuyuki; Tokuda, Shinji; Ishizawa, Tomoko*; Ozeki, Takahisa
no journal, ,
no abstracts in English
