Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nishitani, Takeo; Yamauchi, Michinori*; Nishio, Satoshi; Wada, Masayuki*
Fusion Engineering and Design, 81(8-14), p.1245 - 1249, 2006/02
Times Cited Count：13 Percentile：65.77(Nuclear Science & Technology)no abstracts in English
Yamauchi, Michinori*; Nishitani, Takeo; Nishio, Satoshi
Denki Gakkai Rombunshi, A, 125(11), p.943 - 946, 2005/11
Considering the geometrical characteristics of tokamak reactors with low aspect ratio, a basic neutronics strategy was derived to construct the inboard structure mainly for neutron shielding and produce enough tritium in the outboard blanket. The designs for optimal inboard shield were surveyed and necessary thickness was estimated to make the neutron flux low enough on the super-conducting magnet. In addition, the outer blanket designs were studied to attain the tritium breeding ratio (TBR) large enough for a self-sustaining fusion reactor on the basis of the advanced fusion reactor materials.
Sengoku, Seio
Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.940 - 943, 2004/11
Recent spherical tokamak (ST) experiments exhibit many advantageous results including plasma start-up without center solenoid, higher fraction of non-inductive current, formation of internal thermal-barrier as seen on conventional tokamak. In order to reflect these efforts on the design of so called "non-inductive steady-state (SS) operation scenario" and "current ramp-up scenario" of low-aspect reactor, fractions of bootstrap current and neutral-beam-driven current on VECTOR-OPT reactor are estimated. The operation with this SS scenario is shown to be feasible if the normalized beta, 
n, is raised to grater than 5 typical in ST.
Tani, Keiji; Tobita, Kenji; Nishio, Satoshi; Iio, Shunji*; Tsutsui, Hiroaki*; Aoki, Takayuki*
Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.931 - 934, 2004/11
Studies were made on ripple losses of fusion produced alpha particles in a low-aspect-ratio tokamak reactor (VECTOR) by using an orbit-following Monte-Carlo code. Alpha particles are well confined in VECTOR. In a low-aspect-ratio tokamak, the dependence of ripple losses on the number of toroidal-field (TF) coils N is very weak. Assuming a toroidal peaking factor of 2 for the heat load due to loss particles, about 1.5% and 1.0% of TF ripple at the outer edge of plasma might be allowable for the first wall with and without cooling system, respectively. In both cases, the number of TF-coils can be reduced to about 4.
ballooning modes in tokamaksFurukawa, Masaru; Tokuda, Shinji; Wakatani, Masahiro*
Nuclear Fusion, 43(6), p.425 - 429, 2003/06
We have found numerically that damping phases appear in the time evolution of the perturbation energy of high- ballooning modes in the presence of toroidal shear flows. The damping dominates exponential growth which occurs in the bad curvature region, resulting in stabilization of ballooning modes. D-shaping of plasma cross-section, reduction of aspect ratio, and arrangement of X-point at inner side of the torus enhance the stabilization effect of the toroidal flow through this mechanism.
ballooning modes in tokamaksFurukawa, Masaru; Tokuda, Shinji; Wakatani, Masahiro*
Nuclear Fusion, 43(6), p.425 - 429, 2003/06
Times Cited Count：10 Percentile：31.59(Physics, Fluids & Plasmas)We have found numerically that damping phases appear in the time evolution of the perturbation energy of high- ballooning modes in the presence of toriodal flow shear, where n is a toroidal mode number. The damping dominates exponential growth which occurs in the bad curvature region, resulting in stabilization of ballooning modes. D-shaping of plasma cross-section, reduction of aspect ratio, and arrangement of an X-point at inner side of the torus enhance the stabilization effect of the toroidal flow shear through this mechanism.
JAERI-M 91-081, 607 Pages, 1991/06
no abstracts in English
