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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:32 パーセンタイル:88.47(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:23 パーセンタイル:80.5(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

Current status of the engineering design of the test modules for the IFMIF

山本 道好; Arbeiter, F.*; 横峯 健彦*; 若井 栄一; Theile, J.*; Garcia, A. S.*; Rapisarda, D. S.*; Casal, N. I.*; Mas, A. S.*; Gouat, P.*; et al.

Fusion Engineering and Design, 88(6-8), p.746 - 750, 2013/10

 被引用回数:12 パーセンタイル:73.42(Nuclear Science & Technology)

国際核融合材料照射施設(IFMIF)の工学実証・工学設計活動(EVEDA)はBA協定に基づき2007年半ばから実施されている。IFMIFは加速器, リチウムターゲット設備及び試験設備の3つの主要設備から構成される。現在のEVEDAフェーズではIFMIFの統合設計を目的にしており、その中間報告書は2013年半ばに完成が予定されている。IFMIFの主要な目標であるDEMO炉や将来炉用の設計用の材料データを整備するために、高照射試験モジュール(HFTM、起動時モニターモジュール)、中照射試験モジュール(クリープ疲労試験モジュール, トリチウム試験モジュール, 液体増殖モジュール)及び低照射試験モジュールを用いた照射試験を長期間安定して実施する必要がある。本報告はEVEDAフェーズにおいて複数の協力機関で実施中のこれら各試験のモジュールの工学設計の進捗状況を統合設計の観点で統合したものである。また、中間報告書以後のフェーズにおいて解決すべき技術課題についてまとめる。

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

Current ramps in tokamaks; From present experiments to ITER scenarios

Imbeaux, F.*; Citrin, J.*; Hobirk, J.*; Hogeweij, G. M. D.*; K$"o$chl, F.*; Leonov, V. M.*; 宮本 斉児; 中村 幸治*; Parail, V.*; Pereverzev, G. V.*; et al.

Nuclear Fusion, 51(8), p.083026_1 - 083026_11, 2011/08

 被引用回数:35 パーセンタイル:84.28(Physics, Fluids & Plasmas)

In order to prepare adequate current ramp-up and ramp-down scenarios for ITER, present experiments from various tokamaks have been analysed by means of integrated modelling in view of determining relevant heat transport models for these operation phases. A set of empirical heat transport models for L-mode has been validated on a multi-machine experimental dataset for predicting the $$l_i$$ dynamics within $$pm$$0.15 accuracy during current ramp-up and ramp-down phases. The most accurate heat transport models are then applied to projections to ITER current ramp-up, focusing on the baseline inductive scenario (main heating plateau current of $$I_p = 15$$ MA). These projections include a sensitivity study to various assumptions of the simulation. While the heat transport model is at the heart of such simulations, more comprehensive simulations are required to test all operational aspects of the current ramp-up and ramp-down phases of ITER scenarios. Recent examples of such simulations, involving coupled core transport codes, free-boundary equilibrium solvers and a poloidal field (PF) systems controller are also described, focusing on ITER current ramp-down.

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

Current ramps in tokamaks; From present experiments to ITER scenarios

Imbeaux, F.*; Basiuk, V.*; Budny, R.*; Casper, T.*; Citrin, J.*; Fereira, J.*; 福山 淳*; Garcia, J.*; Gribov, Y. V.*; 林 伸彦; et al.

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

In order to prepare adequate current ramp-up and ramp-down scenarios for ITER, present experiments from various tokamaks have been analysed by means of integrated modelling in view of determining relevant heat transport models for these operation phases. The most accurate heat transport models are then applied to projections to ITER current ramp-up, focusing on the baseline inductive scenario (main heating plateau current of Ip = 15 MA). These projections include a sensitivity studies to various assumptions of the simulation. Recent examples of such simulations, involving coupled core transport codes, free boundary equilibrium solvers and a poloidal field (PF) systems controller are described in the second part of the paper, focusing on ITER current ramp-down.

論文

Current ramps in tokamaks; From present experiments to ITER scenarios

Imbeaux, F.*; Basiuk, V.*; Budny, R.*; Casper, T.*; Citrin, J.*; Fereira, J.*; 福山 淳*; Garcia, J.*; Gribov, Y. V.*; 林 伸彦; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2010/10

ITERでの電流立ち上げ・立ち下げシナリオの準備に向けて、これら運転状態においてどの熱輸送モデルが適切であるかを決定するために、代表的なトカマクでの現在の実験結果を統合モデルシミュレーションにより解析した。本研究では、トカマク実験の解析結果をもとに、ITER標準誘導運転(プラズマ電流15MA)の電流立ち上げ・立ち下げシナリオでの予測を行った。統合モデルシミュレーション結果を、ASDEX Upgrade, C-Mod, DIII-D, JET, Tore Supraのオーミック加熱プラズマ及び外部加熱・電流駆動プラズマ実験データと比較することにより、さまざまな輸送モデルの検証を行った。最も実験結果の再現性の良かった幾つかのモデルを用いて、ITERの電流立ち上げ・立ち下げ段階での電子密度・電流密度プロファイルの予測を行った。電子温度プロファイルには輸送モデルによって大きな差が見られたが、最終的な電流密度プロファイルはモデル間でよく一致することがわかった。

論文

ERL09 WG1 summary; DC gun technological challenges

西森 信行; Bazarov, I.*; Dunham, B.*; Grames, J.*; Hernandez-Garcia, C.*; Jones, L.*; Militsyn, B.*; Poelker, M.*; Surles-Law, K.*; 山本 将博*

Proceedings of 45th Advanced ICFA Beam Dynamics Workshop on Energy Recovery Linacs (ERL '09) (Internet), p.6 - 23, 2009/06

This paper summarizes technological challenges of photoemission DC guns being developed for the future energy recovery linac (ERL) light sources (LS). Anticipated new applications of ERL-LS demand an electron gun capable of producing an extremely low emittance beam at very high average current. The low emittance requires unprecedentedly high voltage equal to or greater than 500 kV between cathode/anode electrodes together with high accelerating gradient on the photocathode. The technological challenge is to develop a high voltage insulator system, which can withstand field emission from the electrodes. The high average current requires prolonged cathode life time, which is governed by ion back-bombardment. Challenges to mitigate the cathode damage caused by ion back-bompardment are surveyed. A gun geometry satisfying both high gun voltage and high accelerating gradient is also proposed.

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。

論文

Photocathodes for the energy recovery linacs

Rao, T.*; Burrill, A.*; Chang, X. Y.*; Smedley, J.*; 西谷 智博; Hernandez Garcia, C.*; Poelker, M.*; Seddon, E.*; Hannon, F. E.*; Sinclair, C. K.*; et al.

Nuclear Instruments and Methods in Physics Research A, 557(1), p.124 - 130, 2006/02

 被引用回数:56 パーセンタイル:96.53(Instruments & Instrumentation)

近年、次期光源や高エネルギー核物理学に用いるエネルギー回収型線形加速器(ERL)の利用が注目を浴びている。ERLが要求する電子源性能は、電流値、電流密度、繰り返し、温度や加速勾配など広範囲に渡る。これらの性能を実現する電子源として、光陰極電子源が重要な役割を果たすと考えられている。本論文では、ERLを実現しうる二次電子放出型、セシウム付加ディスペンサー型、フィールドエミッタ型や超格子半導体の光陰極電子源について概論を提供する。

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

Comparative modeling of JT-60U and JET discharges

林 伸彦; Garcia, J.*; 成田 絵美

no journal, , 

Validation and verification of models for plasma simulation are being carried out through a JA-EU cooperation, especially to make reliable recipe for JT-60SA prediction. The same recipe is, of course, applicable to ITER prediction. In this activity, JT-60U and JET data are used for validation (H-mode and advanced inductive plasmas, at present), and integrated modeling codes TOPICS and CRONOS are used for verification. The following results are obtained at present. As for three heat transport models (CDBM, Bohm/gyro-Bohm, GLF23), in H-mode plasma, CDBM and BgB models can be used for rough estimation, while GLF23 for more precise estimation. On the other hand, in advanced inductive plasma, CDBM is more reliable than GLF23. For this plasma, it is necessary to try TGLF, which is improved version of GLF23. As for particle transport model, GLF23 could reproduce experiments in CRONOS. As for pedestal model, Cordey's scaling model could reproduce experiments in CRONOS. This pedestal model, however, requires pedestal width model for prediction. For this, EPED scaling or peeling-ballooning mode analysis will be applied. TOPICS will verify the above particle and pedestal modelings.

口頭

Modeling of JT-60SA operational scenarios

Garzotti, L.*; Barbato, E.*; Garcia, J.*; Romanelli, M.*; Stankiewicz, R.*; 林 伸彦; 吉田 麻衣子

no journal, , 

JT-60SA scenarios have been simulated with different codes and transport models. Aim of the simulations was to assess stationary conditions estimated with 0-dimensional codes and provide a profile database for further physics studies. Three scenarios considered are standard H-mode, hybrid, advanced steady-state. Codes deployed are ASTRA, CRONOS, JINTRAC. Core transport models used are TGLF (CRONOS), CDBM (CRONOS), GLF23 (ASTRA, CRONOS), Bohm/gyro-Bohm (ASTRA, JINTRAC). Edge transport barrier models are continuous ELMs (JINTRAC), Cordey scaling + EPED1 (CRONOS). Boundary conditions are imposed at separatrix (CRONOS JINTRAC) or top of the pedestal (ASTRA). Fully predictive simulations of current density, ion density (CRONOS and JINTRAC, density not evolved in ASTRA), ion and electron temperature. No rotation. Equilibrium solver SPIDER or three moments (ASTRA), HELENA (CRONOS) and ESCO (JINTRAC). Results are close to those obtained with zero-dimensional codes. Detail of the profiles differ from code to code. Electron and ion temperatures assumed in zero-dimensional calculations seem to be optimistic for most scenarios. For all scenarios normalized pedestal pressure seems to be below MHD stability limit. Further analysis of pedestal stability is required. Analysis of time dependent scenarios (density and current ramp up and down) is planned.

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

Validation of heat transport models with ITB plasmas in JT-60U and JET

Garcia, J.*; 林 伸彦

no journal, , 

JT-60UとJETのITBプラズマの実験データを用いて、3つの熱輸送モデル(CDBM, BgB, GLF23)の妥当性を確認する。合わせて、それらの輸送モデルを用いて2つの統合コードTOPICSとCRONOSの結果を比較し、モデルの検証も行う。JT-60Uの3つの放電とJETの1つの放電のデータを用いて、実験の密度分布固定で、実験のイオン・電子温度分布が熱輸送モデルで再現できるか調べた。TOPICSとCRONOSは概ね同じ結果となり、以下の事が分かった。全ての放電に対して常に実験を再現できるモデルはなかった。しかし、CDBMモデルは実験に近いか低い温度になるので、保守的な性能予測に使える。また、現状のCDBMモデルにE$$times$$Bシアの効果を加えると実験を再現できるようになるが、放電毎にモデルパラメータを変える必要があり、そのモデル化が必要である。BgBモデルは、実験に近い場合もあるし、温度が低かったり高かったりする場合がある。これは、BgBモデルには上記と似たE$$times$$Bシア効果が導入されており、そのモデルパラメータの問題をもつためである。GLF23は、温度が常に実験より低くなった。これは、モデル自体が密度分布を固定した計算に適していない可能性が考えられる。

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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