Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 237

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Simulation study of power load with impurity seeding in advanced divertor "short super-X divertor" for a tokamak reactor

Asakura, Nobuyuki; Hoshino, Kazuo; Shimizu, Katsuhiro; Shinya, Kichiro*; Uto, Hiroyasu; Tokunaga, Shinsuke; Tobita, Kenji; Ono, Noriyasu*

Journal of Nuclear Materials, 463, p.1238 - 1242, 2015/08

 Times Cited Count:11 Percentile:67.6(Materials Science, Multidisciplinary)

Arrangements of interlink divertor coils and divertor geometries for short super-X was proposed as the Demo advanced divertor design. Performance of plasma detachment under the large heat flux was investigated to optimize the divertor design, using SONIC simulation with Ar impurity seeding, where Pout = 500 MW, ne = 7$$times$$10$$^{19}$$ m$$^{-3}$$ at the core-edge boundary and the same diffusion coefficients for ITER simulation. Effects on the plasma temperature and density distributions were compared to the conventional divertor. The first run results with the same radiation power fraction of 0.92 in the conventional divertor showed that full detached plasma is produced, the maximum radiation region was maintained upstream the divertor target, and both the plasma heat load plus radiation load at the target was reduced to 10 MWmm$$^{-2}$$ level. Simulation for the lower radiation power fractions of 0.8-0.9 was also performed, and physics issues of the short super-X divertor are discussed.

Journal Articles

The Influence of the radial particle transport on the divertor plasma detachment

Hoshino, Kazuo; Shimizu, Katsuhiro; Takizuka, Tomonori*; Asakura, Nobuyuki; Nakano, Tomohide

Journal of Nuclear Materials, 463, p.573 - 576, 2015/08

 Times Cited Count:10 Percentile:67.6(Materials Science, Multidisciplinary)

Journal Articles

Advance in integrated modelling towards prediction and control of JT-60SA plasmas

Hayashi, Nobuhiko; Honda, Mitsuru; Shiraishi, Junya; Miyata, Yoshiaki; Wakatsuki, Takuma; Hoshino, Kazuo; Toma, Mitsunori; Suzuki, Takahiro; Urano, Hajime; Shimizu, Katsuhiro; et al.

Europhysics Conference Abstracts (Internet), 39E, p.P5.145_1 - P5.145_4, 2015/06

Journal Articles

Studies of impurity seeding and divertor power handling in fusion reactor

Hoshino, Kazuo; Asakura, Nobuyuki; Shimizu, Katsuhiro; Tokunaga, Shinsuke

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 6 Pages, 2014/10

Journal Articles

Development of the backflow model for simplified impurity exhaust in Monte-Carlo calculation

Hoshino, Kazuo; Shimizu, Katsuhiro; Kawashima, Hisato; Takizuka, Tomonori*; Nakano, Tomohide; Ide, Shunsuke

Contributions to Plasma Physics, 54(4-6), p.404 - 408, 2014/06

 Times Cited Count:16 Percentile:61.44(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Simple and fast Poisson solver with arbitrary boundary shape and condition for PIC simulation

Takizuka, Tomonori*; Azuma, Shuhei*; Fukuyama, Atsushi*; Shimizu, Katsuhiro

Contributions to Plasma Physics, 54(4-6), p.388 - 393, 2014/06

 Times Cited Count:1 Percentile:5.7(Physics, Fluids & Plasmas)

Particle-in-cell (PIC) simulations are the very powerful method to understand physics of edge plasmas in fusion devices. Poisson solver with a regular grid in a rectangular vessel is very fast, but it cannot simply be applicable to simulations in complicated divertor configuration. In this paper, a simple and fast Poisson solver with arbitrary boundary shape and condition for PIC simulation is proposed. Boundary points are essential for this Poisson solver, on which the charge density is appropriately given and the boundary condition is satisfied. For particle simulations in the open system, it is necessary to distinguish whether a traced particle moves freely or hits the wall boundary during a time step. A new method for PIC simulation to discriminate a particle position before the boundary or beyond the boundary is also presented.

Journal Articles

Divertor study on DEMO reactor

Hoshino, Kazuo; Asakura, Nobuyuki; Shimizu, Katsuhiro; Tokunaga, Shinsuke; Takizuka, Tomonori*; Someya, Yoji; Nakamura, Makoto; Uto, Hiroyasu; Sakamoto, Yoshiteru; Tobita, Kenji

Plasma and Fusion Research (Internet), 9(Sp.2), p.3403070_1 - 3403070_8, 2014/06

no abstracts in English

Journal Articles

A Simulation study of large power handling in the divertor for a Demo reactor

Asakura, Nobuyuki; Shimizu, Katsuhiro; Hoshino, Kazuo; Tobita, Kenji; Tokunaga, Shinsuke; Takizuka, Tomonori*

Nuclear Fusion, 53(12), p.123013_1 - 123013_15, 2013/12

 Times Cited Count:48 Percentile:90.76(Physics, Fluids & Plasmas)

Power exhaust scenario for 3 GW fusion reactor has been developed with enhancing the radiation loss from seeding impurity. Impurity transport and plasma detachment were simulated self-consistently under the Demo divertor condition using an integrated divertor code SONIC. Power handling with different seeding impurities showed that the total heat load, including the plasma transport and radiation, was reduced from 15 MW/m$$^{2}$$ to 10 MW/m$$^{2}$$ for the higher Z case, where both heat load components became comparable. Effects of a long-leg divertor were examined. Full detachment was obtained and peak heat load was decreased to 12 MW/m$$^{2}$$, where neutral load became comparable to the plasma and radiation load, which may be due to small flux expansion. Finally, plasma diffusion significantly affected the performance of the plasma detachment. Peak heat lard was reduced to 5 MW/m$$^{2}$$ well below engineering design level, with uniformly increasing the diffusion coefficient by the factor of two.

Journal Articles

Investigation of advanced divertor magnetic configuration for DEMO tokamak reactor

Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.

Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05

no abstracts in English

Journal Articles

Investigation of advanced divertor magnetic configuration for Demo tokamak reactor

Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.

Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05

 Times Cited Count:13 Percentile:69.84(Nuclear Science & Technology)

Design study of poloidal field coil (PFC) locations and current distribution for the advanced divertor in the Demo tokamak reactor was presented. Concept of the super-X divertor (SXD) for Demo reactor has an outer divertor leg longer than the conventional divertor, and it extends outboard to increase both the target wetted area and connection length to the outer target ($$L_{//}$$). Equilibrium calculation code, TOSCA, was developed by introducing two parameters, i.e. super-X null radius ($$R_{SX}$$) and a ratio of the poloidal flux at the super-X null to that at the separatrix ($$f_{SX}$$). Some SXD magnetic configurations with minimal number of PFCs located outside toroidal field coil (TFC) were Demonstrated. Locations of the divertor target were also investigated. It was found that the flux expansion can be increased up to 4-10 depending on the target location and $$f_{SX}$$, and that SXD has an advantage to increase $$L_{//}$$ with $$f_{SX}$$. Thus, the divertor plasma temperature is expected to decrease at the same upstream plasma density. On the other hand, large currents for the divertor PFCs were necessary. Other arrangements of PFCs such as (1) larger $$R_{SX}$$ and (2) inside TFC, can reduce the PFC currents.

Journal Articles

Optimization of JT-60SA plasma operational scenario with capabilities of installed actuators

Ide, Shunsuke; Aiba, Nobuyuki; Bolzonella, T.*; Challis, C. D.*; Fujita, Takaaki; Giruzzi, G.*; Joffrin, E.*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Honda, Mitsuru; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03

Journal Articles

In-vessel tritium

Ueda, Yoshio*; Oya, Kaoru*; Ashikawa, Naoko*; Ito, Atsushi*; Ono, Tadayoshi*; Kato, Daiji*; Kawashima, Hisato; Kawamura, Gakushi*; Kenmotsu, Takahiro*; Saito, Seiki*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 88(9), p.484 - 502, 2012/09

no abstracts in English

Journal Articles

Simulation study of an extended divertor leg for heat control in the SlimCS DEMO reactor

Hoshino, Kazuo; Shimizu, Katsuhiro; Asakura, Nobuyuki; Takizuka, Tomonori; Nakamura, Makoto; Tobita, Kenji

Contributions to Plasma Physics, 52(5-6), p.550 - 554, 2012/06

 Times Cited Count:21 Percentile:66.41(Physics, Fluids & Plasmas)

The power handling in the divertor is one of the most important issues for fusion tokamak reactor design. In this study, the effect of the divertor leg length on the power handling in the SlimCS DEMO reactor is investigated for future divertor design. The SONIC simulation shows enhancement of recycling in the outer divertor region due to effects of the long divertor leg and deep V-shaped corner. As a result, the ion and electron temperature at the outer divertor significantly decreases. In addition, peak of the Ar impurity radiation, which is located close to the outer divertor target in the standard divertor geometry, moves upstream. The former decreases the heat load to the outer divertor due to the ion conduction and convection, and the latter reduces the heat load due to the impurity radiation. The peak of the total heat load on the outer divertor decreases by about 30%.

Journal Articles

Simulation study of L/H transition with self-consistent integrated modelling of core and SOL/divertor transport

Yagi, Masatoshi; Shimizu, Katsuhiro; Takizuka, Tomonori; Honda, Mitsuru; Hayashi, Nobuhiko; Hoshino, Kazuo; Fukuyama, Atsushi*

Contributions to Plasma Physics, 52(5-6), p.372 - 378, 2012/06

 Times Cited Count:5 Percentile:22.06(Physics, Fluids & Plasmas)

Journal Articles

Evaluation of heat and particle controllability on the JT-60SA divertor

Kawashima, Hisato; Hoshino, Kazuo; Shimizu, Katsuhiro; Takizuka, Tomonori; Ide, Shunsuke; Sakurai, Shinji; Asakura, Nobuyuki

Journal of Nuclear Materials, 415(Suppl.1), p.S948 - S951, 2011/08

 Times Cited Count:8 Percentile:53.54(Materials Science, Multidisciplinary)

The divertor design of the JT-60SA tokamak device is finalized according to the engineering requirements and the physical analyses with the SONIC code simulations. Assuming the steady-state high beta core plasmas with 41 MW heating power, high heat and particle fluxes flowing out from core to SOL arrive at the divertor targets and give a large heat load. From the engineering viewpoint, the allowable heat load is restricted below 15 MW/m$$^{2}$$ by the tolerability of the target material and structure. As a scenario to reduce the heat load, the vertical target configuration is adopted to receive the heat load on the wide area. In addition, the V-shaped corner is set to enhance the recycling at the outer side divertor where receives a relatively large heat load. Then, the remote radiative cooling is optimized by control of the D$$_{2}$$ gas puffing, the impurity seeding and the divertor pumping.

Journal Articles

Improvement of the detachment modelling in the SONIC simulation

Hoshino, Kazuo; Shimizu, Katsuhiro; Takizuka, Tomonori; Asakura, Nobuyuki; Nakano, Tomohide

Journal of Nuclear Materials, 415(Suppl.1), p.S549 - S552, 2011/08

 Times Cited Count:10 Percentile:61.04(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Inward pinch of high-Z impurity in a rotating tokamak plasma; Effects of atomic processes, radial electric field and Coulomb collisions

Hoshino, Kazuo; Toma, Mitsunori*; Shimizu, Katsuhiro; Nakano, Tomohide; Hatayama, Akiyoshi*; Takizuka, Tomonori

Nuclear Fusion, 51(8), p.083027_1 - 083027_6, 2011/08

 Times Cited Count:5 Percentile:23.46(Physics, Fluids & Plasmas)

Journal Articles

Integrated modeling of whole tokamak plasma

Hayashi, Nobuhiko; Honda, Mitsuru; Hoshino, Kazuo; Hamamatsu, Kiyotaka; Shimizu, Katsuhiro; Takizuka, Tomonori; Ozeki, Takahisa; Fukuyama, Atsushi*

Plasma and Fusion Research (Internet), 6(Sp.1), p.2403065_1 - 2403065_8, 2011/08

Journal Articles

Inward pinch of high-Z impurity due to atomic processes in a rotating tokamak plasma and the effect of radial electric field

Hoshino, Kazuo; Toma, Mitsunori*; Shimizu, Katsuhiro; Nakano, Tomohide; Hatayama, Akiyoshi*; Takizuka, Tomonori

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03

The transport of high-Z impurity in a toroidally rotating tokamak plasma is investigated analytically and numerically. It is shown that the inward pinch is driven by the atomic processes in co- and ctr- rotating plasmas. This inward pinch is enhanced by the radial electric field. It is derived that the negative and positive radial electric fields cause the inward pinch and the outward movement (unpinch) of the high-Z impurity, respectively, under the influence of Coulomb collisions with the rotating background plasma. In the ctr-rotation case, the inward pinch becomes significant with increasing toroidal rotation velocity, because the directions of the both pinches are inward. On the other hand, in the co-rotation case, these pinches have opposite directions. Therefore, the unpinch due to the positive radial electric field is decreased by the inward pinch due to the atomic processes. These tendencies are consistent with the tungsten accumulation observed in the JT-60U.

Journal Articles

Self-consistent integrated modelling of core and SOL/divertor transports and simulation study on transient behavior of heat load on divertor targets

Shimizu, Katsuhiro; Takizuka, Tomonori; Hoshino, Kazuo; Honda, Mitsuru; Hayashi, Nobuhiko; Takayama, Arimichi*; Fukuyama, Atsushi*; Yagi, Masatoshi*

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03

We have developed a self-consistent integrated modelling of core and SOL/divertor transport. Thereby it enables us to investigate operation scenarios to be compatible with high confinement core plasma and detached divertor plasmas. To integrate a 1.5D core code (TOPICS-IB and TASK) and a 2D divertor code (SONIC), we introduce a new Multiple Program Multiple Data parallel computing system. For an integrated code including Monte-Carlo calculations, this system makes it possible to perform efficient simulations. The predictive simulation studies are carried out for JT-60SA with the integrated code (TOPICS-IB/SONIC) and the characteristics of the divertor heat load after the H-mode transition is clarified. We also discuss about the temporal behavior of divertor characteristics after an ELM crash.

237 (Records 1-20 displayed on this page)