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論文

Physics comparison and modelling of the JET and JT-60U core and edge; Towards JT-60SA predictions

Garcia, J.*; 林 伸彦; Baiocchi, B.*; Giruzzi, G.*; 本多 充; 井手 俊介; Maget, P.*; 成田 絵美*; Schneider, M.*; 浦野 創; et al.

Nuclear Fusion, 54(9), p.093010_1 - 093010_13, 2014/09

 被引用回数:31 パーセンタイル:9.6(Physics, Fluids & Plasmas)

Extensive physics analysis and modelling has been undertaken for the typical operational regimes of the tokamak devices JET and JT-60U with the aim of extrapolating present day experiments to JT-60SA, which shares important characteristics with both tokamaks. A series of representative discharges of two operational scenarios, H-mode and hybrid, have been used for this purpose. Predictive simulations of core turbulence, particle transport, current diffusion and pedestal pressure have been carried out with different combinations of models. The ability of the models for reproducing the experimental data is analysed and scenario calculations for JT-60SA are performed following an optimum set of models.

論文

Analysis of JT-60SA scenarios on the basis of JET and JT-60U discharges

Garcia, J.*; 林 伸彦; Giruzzi, G.*; Schneider, M.*; Joffrin, E.*; 井手 俊介; 坂本 宜照; 鈴木 隆博; 浦野 創; JT-60チーム; et al.

Europhysics Conference Abstracts (Internet), 38F, p.P1.029_1 - P1.029_4, 2014/06

Creation of JT-60SA scenarios is necessary in order to make deeper analyses: Fast ions, heating schemes, MHD. Validation exercise: a series of representative discharges of the three main operational scenarios, H-mode, hybrid and steady-state have been selected for each device in order to extrapolate to JT-60SA. An extensive analysis of the main physics similarities and differences among the discharges has been carried out in order to explain results. Using integrated modelling codes CRONOS and TOPICS, benchmark of the codes is done. Predictive core turbulence simulations have been carried out with three transport models: Bohm-GyroBohm, CDBM and GLF23. Particle transport is analyzed with GLF23. Pressure pedestal predictions are simulated with Cordey MHD scaling. Fully predictive simulations of temperatures, density and pedestal have been performed with GLF23 and CDBM models for the temperatures and GLF23 for the density. Calculations for JT-60SA are performed following the best combination of models found.

論文

Development of advanced inductive scenarios for ITER

Luce, T. C.*; Challis, C. D.*; 井手 俊介; Joffrin, E.*; 鎌田 裕; Politzer, P. A.*; Schweinzer, J.*; Sips, A. C. C.*; Stober, J.*; Giruzzi, G.*; et al.

Nuclear Fusion, 54(1), p.013015_1 - 013015_15, 2013/12

 被引用回数:20 パーセンタイル:22.07(Physics, Fluids & Plasmas)

The ITPA IOS group has coordinated experimental and modeling activity on the development of advanced inductive scenarios for applications in the ITER tokamak. This report documents the present status of the physics basis and the prospects for applications in ITER. The key findings are: (1) inductive scenarios capable of higher $$beta_{rm N} ge 2.4$$ than the ITER baseline scenario ($$beta_{rm N} = 1.8$$) with normalized confinement at or above the standard H-mode scaling have been established under stationary conditions on the four largest diverted tokamaks (AUG, DIII-D, JET, JT-60U) in a broad range in $$q_{rm 95}$$ and density; (2) MHD modes can play a key role in reaching stationary high performance, but also define the stability and confinement limits; (3) the experiments have yielded clearer measurements of the normalized gyroradius scalin; and (4) coordinated modeling activity supports the present research by clarifying the most significant uncertainties in the projections to ITER.

論文

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

井手 俊介; 相羽 信行; Bolzonella, T.*; Challis, C. D.*; 藤田 隆明; Giruzzi, G.*; Joffrin, E.*; 濱松 清隆; 林 伸彦; 本多 充; et al.

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

Assessment of capabilities in controlling key plasma parameters to access and sustain a high normalized pressure plasma in JT-60SA has been carried out using predictive simulations with emphasis on controllability with actuators, including not only heating and current drive but also fueling and pumping system. It is confirmed that the safety factor profile, which is believed to play an important role for confinement improvement, can be prepared appropriately at the plasma current ramp-up phase in a wide extent within capability of the installed ECRF system. At the flat-top of a high pressure and high bootstrap current plasma, it is also confirmed that the installed NB system can modify the safety factor profile and the confinement property within the planned capabilities. It is confirmed that impurity seeding in the SOL and the divertor region can maintain the heat flux within the divertor heat tolerance keeping the separatrix density level acceptable.

論文

Model validation and integrated modelling simulations for the JT-60SA tokamak

Giruzzi, G.*; Garcia, J.*; 林 伸彦; Schneider, M.*; Artaud, J. F.*; Baruzzo, M.*; Bolzonella, T.*; Farina, D.*; Figini, L.*; 藤田 隆明; et al.

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

A coordinated Japan-EU modelling activity has started in order to provide predictive simulations of the main JT-60SA scenarios. The first results of this activity are discussed in this paper. This includes: (1) the critical comparison and benchmark of Japanese and EU H and CD codes, in particular of NBI codes for the complex injector configuration of the JT-60SA machine; (2) the validation of the main models and simulation framework used in both Japanese and EU integrated modelling suites of codes, based on selected reference discharges of JT-60U and JET, representing the main scenarios (H-mode, hybrid, advanced); (3) predictive modelling of JT-60SA scenario, using the 0.5-D code METIS.

論文

Integrated modelling of JT-60SA scenarios with the METIS code

Giruzzi, G.*; Artaud, J. F.*; Joffrin, E.*; Garcia, J.*; 井手 俊介; JT-60SA Research Plan Contributors; JT-60SAチーム

Europhysics Conference Abstracts (Internet), 36F, p.P5.018_1 - P5.018_4, 2012/00

Here, sets of simulations of the main JT-60SA operation scenarios performed with the 0.5-D code METIS will be presented and discussed. METIS computes the time evolution of the global plasma quantities for given waveforms of the control parameters. It solves the current diffusion equation taking into account an approximate equilibrium evolution. Simplified treatment of the sources and of spatial dependences allow simulation of a discharge in a CPU time of the order of one minute, while keeping account of all the main non-linearities of the evolution. This approach allows completing the 0-D analysis with radial profiles and time evolutions. Evaluation of scalar parameters of a few JT-60SA scenario such as the normalized beta by METIS is found to be close those evaluated by ACCOME.

論文

Comparative transport analysis of JET and JT-60U discharges

Garcia, J.*; 林 伸彦; Giruzzi, G.*; Schneider, M.*; Joffrin, E.*; 井手 俊介; 坂本 宜照; 鈴木 隆博; 浦野 創; JT-60チーム; et al.

Europhysics Conference Abstracts (Internet), 36F, p.P5.057_1 - P5.057_4, 2012/00

Predictive simulations for electron and ion temperatures have been carried out for JET and JT-60U plasmas in order to determine the most appropriate models to this type of plasmas. To carry out this programme, the integrated modelling codes CRONOS and TOPICS-IB are used. Results show that the H-modes are usually well simulated for both devices, whereas for the advanced regimes, as the hybrid, there are clear deviations from experimental data, mainly for JT-60U. The reasons for such discrepancies are analysed.

論文

Integrated modeling of steady-state scenarios and heating and current drive mixes for ITER

村上 和功*; Park, J. M.*; Giruzzi, G.*; Garcia, J.*; Bonoli, P.*; Budny, R. V.*; Doyle, E. J.*; 福山 淳*; 林 伸彦; 本多 充; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

Recent progress on ITER steady-state scenario modeling by the ITPA-IOS group is reviewed. Code-to-code benchmarks as the IOS group's common activities for the two steady-state scenarios (weak shear scenario and internal transport barrier scenario) are reviewed. These are discussed in terms of transport and kinetic profiles, heating and CD sources using various transport codes.

論文

Experimental studies of ITER demonstration discharges

Sips, A. C. C.*; Casper, T.*; Doyle, E. J.*; Giruzzi, G.*; Gribov, Y.*; Hobirk, J.*; Hogeweij, G. M. D.*; Horton, L. D.*; Hubbard, A. E.*; Hutchinson, I.*; et al.

Nuclear Fusion, 49(8), p.085015_1 - 085015_11, 2009/08

 被引用回数:46 パーセンタイル:11.25(Physics, Fluids & Plasmas)

ITERにおける放電の時間発展に関して、実験的に検証した。すなわち、着火から電流立ち上げ,電流フラットトップ,電流立ち下げである。着火に関しては、JETのような大型トカマクではECRFによる補助なしで、またECRFによる補助が有る場合にはすべての装置でITERの要求である一周電界$$leq$$0.35V/mでの着火を確認できた。立ち上げ時には、早期にダイバータ移行し大きなプラズマ断面を早くに形成することによりインダクタンスをよく制御できることがわかった。フラットトップでの種々の特性、特にH-mode遷移後と逆遷移後のインダクタンスの変化についてデータが得られた。

論文

Progress in the ITER physics basis, 3; MHD stability, operational limits and disruptions

Hender, T. C.*; Wesley, J. C.*; Bialek, J.*; Bondeson, A.*; Boozer, A. H.*; Buttery, R. J.*; Garofalo, A.*; Goodman, T. P.*; Granetz, R. S.*; Gribov, Y.*; et al.

Nuclear Fusion, 47(6), p.S128 - S202, 2007/06

 被引用回数:681 パーセンタイル:3.51(Physics, Fluids & Plasmas)

本論文は、1999年の"ITER Physics Basis"の刊行以降に世界各国の装置で得られた重要な成果について記述したものであり、本章ではMHD安定性及びディスラプションに関する成果が記述されている。MHD安定性に関しては、(1)鋸歯状振動,(2)新古典テアリングモード,(3)抵抗性壁モード,(4)誤差磁場,(5)先進シナリオにおけるMHD安定性に関する成果が記述されていて、ディスラプションに関しては、(1)ディスラプションの特徴・原因・頻度,(2)サーマルクエンチによるエネルギーの損失と堆積,(3)電流クエンチのダイナミクス,(4)ディスラプションにより発生する逃走電子,(5)統合モデルとシミュレーション,(6)ディスラプションの回避・予測・緩和に関する成果が記述されている。

論文

Benchmarking of lower hybrid current drive codes with application to ITER-relevant regimes

Bonoli, P. T.*; Harvey, R. W.*; Kessel, C. E.*; Imbeaux, F.*; 及川 聡洋; Schneider, M.*; Barbato, E.*; Decker, J.*; Giruzzi, G.*; Forest, C. B.*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

ITER定常運転プラズマを対象として、複数の低域混成波(LH)電流駆動計算コードを比較した。LH計算コードには2次元速度空間で定義されたFokker-Planck方程式をもとにしたコード及び1次元Fokker-Planck方程式をもとにしたコードがあり、2次元Fokker-Planckコードは最も適切な取り扱いをしていると考えられる。2次元コードは1次元コードに比べて40%程度大きいLH駆動電流を与えた。また、捕捉粒子効果の考慮も重要であることもわかった。さらに、バウンス平均したオペレータの導入が必要であり、バウンス平均していないオペレータを使った場合30%程度計算結果が異なる。また、核融合生成物である3.5MeVのアルファ粒子によるLH波の吸収を評価した。アルファ粒子の異常輸送によりLH波吸収領域でのアルファ粒子密度が増加する場合でも、LH波周波数3.7GHzにおいてアルファ粒子により吸収されるLHパワーは7.7%と小さく、LH機器の設計値である5GHzに対して周波数選択の余地があることを示した。

論文

Simulation of the hybrid and steady state advanced operating modes in ITER

Kessel, C. E.*; Giruzzi, G.*; Sips, A. C. C.*; Budny, R. V.*; Artaud, J. F.*; Basiuk, V.*; Imbeaux, F.*; Joffrin, E.*; Schneider, M.*; Luce, T.*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

国際トカマク物理活動の定常運転グループでは統合シミュレーションコードのベンチマークを始めており、CRONOS, ONETWO, TRANSP, TOPICS, ASTRAといった複数の1.5次元輸送コードを用いてITERハイブリッド運転のシミュレーションを行った。平衡配位,加熱電流駆動機器のジオメトリ、熱・粒子輸送モデル等について共通ガイドラインを設けて極力同じ計算条件となるようにしている。世界的に利用されている輸送コードのほとんどが参加したベンチマークは初めてであり、結果の違いについて結論できる段階には至っていないが、各コードにおいて改良すべき点を客観的に評価できることを明らかにした。

口頭

Benchmarking of neutral beam current drive codes as a basis for the integrated modeling for ITER

及川 聡洋; Park, J. M.*; Polevoi, A. R.*; Schneider, M.*; Giruzzi, G.*; Murakami, M.*; 谷 啓二*; Sips, A. C. C.*

no journal, , 

出張者は国際トカマク物理活動の統合運転シナリオに関するトピカルグループにおいて、中性粒子ビーム電流駆動(NBCD)の理論コードのベンチマークを主導している。現在までに粒子軌道追跡モンテカルロコードOFMC, NUBEAM, SPOT,フォッカープランク法によるACCOME, ASTRAの計5コードの比較を行ってきた。NB入射による高速イオン生成分布は、異なるビームモデル,電離断面積モデルを使っていてもほぼ一致する。加熱分布はおおむね一致するものの細かい部分での差異が見られる。これは有限軌道幅効果によるもと考えられる。NB電流駆動分布は比較的大きな相違が見られる。OFMC, ACCOMEは高速イオンの初期ピッチ角をトロイダル磁場に対して計算しており、本来のプラズマ平衡磁場に対するピッチ角よりもずれる。このピッチ角計算の修正により、他コードとの差はある程度解消されることが期待できる。ASTRAコードは、実際のNB軌道を簡略化していること、円柱プラズマに対して導出されてフォッカープランク方程式を解いておりトロイダル効果を反映していないことが他コードとのずれの原因であることがわかった。

口頭

JT-60SAプラズマにおける制御範囲の評価とシナリオ開発

井手 俊介; 相羽 信行; Bolzonella, T.*; Challis, C. D.*; 藤田 隆明; Giruzzi, G.*; Joffrin, E.*; 濱松 清隆; 林 伸彦; 本多 充; et al.

no journal, , 

One of the main goals of JT-60SA project is to achieve steady-state sustainment of a high normalized pressure ($$beta_N$$) plasma, which is required in the ITER steady-stat operation and DEMO. Plasma control plays a key role to accomplish this goal. Assessment of capabilities in controlling key plasma parameters to access and sustain a high $$beta_N$$ plasma in JT-60SA has been carried out using TOPICS with emphasis on controllability with actuators, including not only heating and current drive but also fueling and pumping system. It is confirmed that the safety factor profile can be prepared appropriately at the plasma current ramp-up phase within capability of the installed ECRF system. At the flat-top of a high $$beta_N$$ and high bootstrap current plasma, it is also confirmed that the installed NB system can modify the safety factor profile and the confinement property within the planned capabilities. It is confirmed that impurity seeding in the SOL and the divertor region can maintain the heat flux within the divertor heat tolerance keeping the separatrix density level acceptable.

口頭

Physics comparison and modeling of the JET and JT-60U core and edge; Towards JT-60SA predictions

Garcia, J.*; 林 伸彦; Baiocchi, B.*; Citrin, J.*; Giruzzi, G.*; 本多 充; 井手 俊介; Maget, P.*; 成田 絵美*; Schneider, M.*; et al.

no journal, , 

An extensive exercise of physics analysis and modeling has been undertaken for the typical operational regimes of the tokamak devices JET and JT-60U with the aim of extrapolating present day experiments to JT-60SA, which share characteristics with both tokamaks. A series of representative discharges of two operational scenarios, H-mode and hybrid have been used for this purpose. Predictive simulations of core turbulence, particle transport, current diffusion and pedestal pressure have been carried out with different combination of models. The ability of the models for reproducing the experimental data is analyzed and scenario calculations for JT-60SA are performed following an optimum simulation framework.

口頭

Progress in integrated modeling of JT-60SA plasma operation scenarios with model validation and verification

林 伸彦; Garcia, J.*; 本多 充; 清水 勝宏; 星野 一生; 井手 俊介; Giruzzi, G.*; 坂本 宜照; 鈴木 隆博; 浦野 創

no journal, , 

Development of plasma operation scenarios in JT-60SA has been progressing by using integrated modeling codes. In order to obtain an optimum set of models for the prediction, models are validated by using JT-60U and JET experimental data, and verified by integrated codes such as TOPICS and CRONOS. Predictive simulations are performed to assess the performance of each scenario and to develop optimum scenarios. In the scenario development, various physics aspects are studied by using various types of integrated modeling. The integrated divertor code SONIC showed that Ar seeding can reduce the heat flux on divertor plates below the preferable level (10 MW/m$$^{2}$$) with keeping low separatrix density in the full non-inductive current drive scenario, however, there are some amounts of Ar influx to core region. We integrate TOPICS with a core impurity transport code IMPACT and study the Ar accumulation in the core and its effect on the performance. Other studies with integrated modeling will be also presented.

口頭

モデル妥当性確認と検証を伴ったJT-60SAプラズマ運転シナリオの統合モデリング

林 伸彦; Garcia, J.*; 本多 充; 清水 勝宏; 星野 一生; 井手 俊介; Giruzzi, G.*; 坂本 宜照; 鈴木 隆博; 浦野 創

no journal, , 

Development of plasma operation scenarios in JT-60SA has been progressing by using integrated modeling codes. Anomalous heat transport model, which are one of major uncertainties in the prediction, have been validated for ITB plasmas with full current drive (CD) condition in JT-60U and JET, and integrated codes TOPICS and CRONOS equipped with the models are used for the model verification. It is found that CDBM model predicts temperatures close to those in experiments or underestimates them, and thus can be used for the conservative prediction. By using TOPICS with CDBM model, JT-60SA ITB plasmas with high $$beta_N$$ and full CD condition have been predicted consistently with Ar seeding to reduce the heat load on divertor plates below 10 MW/m$$^2$$. In the prediction, TOPICS is coupled with impurity transport code IMPACT to examine the Ar core accumulation for the influx to the core and the separatrix density evaluated by integrated divertor code SONIC. The Ar accumulation is found to be so mild that the performance can be recovered by additional heating. Due to the strong dependence of accumulation on the pedestal density gradient, the high separatrix density is important for low accumulation as well as low divertor heat load.

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