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Development of laser beam injection system for the Edge Thomson Scattering (ETS) in ITER

谷塚 英一; 波多江 仰紀; 水藤 哲*; 小原 美由紀*; 萩田 浩二*; 井上 和典*; Bassan, M.*; Walsh, M.*; 伊丹 潔

Journal of Instrumentation (Internet), 11(1), p.C01006_1 - C01006_12, 2016/01

 被引用回数:5 パーセンタイル:66.58(Instruments & Instrumentation)

In the ITER Edge Thomson Scattering, the penetration in the port plug allows the laser beams to be injected into the plasma. The penetration has to be as small as possible to reduce neutron streaming from the plasma-side. In ITER, multiple laser systems are needed for high availability of Thomson scattering diagnostics. A new type of beam combiner was developed to obtain collinear, i.e. smallest footprint because of the common path, and fixed polarization from multiple laser beams using a rotating half-wave-plate. The rotating half-wave-plate method does not induce misalignment even if the rotating mechanism defects. The combined beam is injected into plasma and is absorbed at the beam dump. The beam alignment system was designed to hit the laser beam onto the center of the beam dump. The beam position at the beam dump head is monitored by multiple alignment laser beams which are collinear with the diagnostic YAG laser beam and an imaging system installed outside the diagnostic port.


Enhancement of resistance against high energy laser pulse injection with chevron beam dump

谷塚 英一; 波多江 仰紀; Bassan, M.*; Vayakis, G.*; Walsh, M.*; 伊丹 潔

Fusion Engineering and Design, 100, p.461 - 467, 2015/11

 被引用回数:3 パーセンタイル:63.46(Nuclear Science & Technology)

This paper reports our recent developments on the laser beam dump for the Edge Thomson Scattering System in ITER. The laser-induced damage on the beam dump surface is one of the most severe issues of the beam dump development to be overcome. In order to resolve the damage issue, a new type of beam dump called the chevron beam dump was proposed recently. This paper aims to verify the key concept of the chevron beam dump design. The laser irradiation tests onto flat-mirror-molybdenum sample were carried out. It was clarified that the absorbed energy density of the laser pulses should be the correct figure of the laser-induced damage. Therefore, the concept of the chevron beam dump, that minimizes the absorbed laser energy density per unit area, was validated experimentally. It was concluded that the chevron beam dump enables us to extend its lifetime drastically relative to conventional beam dumps.


Progresses in development of the ITER edge Thomson scattering system

谷塚 英一; Bassan, M.*; 波多江 仰紀; 石川 正男; 嶋田 恭彦; Vayakis, G.*; Walsh, M.*; Scannell, R.*; Huxford, R.*; Bilkova, P.*; et al.

Journal of Instrumentation (Internet), 8(12), p.C12001_1 - C12001_10, 2013/12

 被引用回数:6 パーセンタイル:62.45(Instruments & Instrumentation)

In ITER, the edge Thomson scattering system (ETS) is one of the primary diagnostic systems for measuring electron temperature and electron density profiles of edge plasma. In order to provide a high throughput of scattered light against a low throughput of neutron and $$gamma$$ ray from plasma, collection optics with a labyrinthine optical path in the port plug was designed. A combination of in-situ calibration (using two lasers with different wavelengths) and periodic calibration (using a super-continuum light source illuminating shutter rear-plate covered with a diffusive material) would provide accurate measurements in ITER against the degradation of spectral transmissivity due to the harsh radiation environment and sputtering/contamination of the first mirror. Specifications of subsystems were determined from assessments of measurement error. It was confirmed that the ETS will work in ITER with the specifications achieved by present technologies.


Port-based plasma diagnostic infrastructure on ITER

Pitcher, C. S.*; Barnsley, R.*; Bertalot, L.*; Encheva, A.*; Feder, R.*; Friconneau, J. P.*; Hu, Q.*; Levesy, B.*; Loesser, G. D.*; Lyublin, B.*; et al.

Fusion Science and Technology, 64(2), p.118 - 125, 2013/08

 被引用回数:4 パーセンタイル:60.1(Nuclear Science & Technology)



Benchmarking of mechanical test facilities related to ITER CICC steel jackets

Vostner, A.*; Pong, I.*; Bessette, D.*; Devred, A.*; Sgobba, S.*; Jung, A.*; Weiss, K.-P.*; Jewell, M. C.*; Liu, S.*; Yu, W.*; et al.

IEEE Transactions on Applied Superconductivity, 23(3), p.9500705_1 - 9500705_5, 2013/06

 被引用回数:11 パーセンタイル:42.25(Engineering, Electrical & Electronic)



Nuclear engineering of diagnostic port plugs on ITER

Pitcher, C. S.*; Barnsley, R.*; Feder, R.*; Hu, Q.*; Loesser, G. D.*; Lyublin, B.*; Padasalagi, S.*; Pak, S.*; Reichle, R.*; 佐藤 和義; et al.

Fusion Engineering and Design, 87(5-6), p.667 - 674, 2012/08

 被引用回数:10 パーセンタイル:31.32(Nuclear Science & Technology)

The nuclear engineering infrastructure for port-based diagnostics on ITER is presented, including the equatorial and upper port plug generic designs, the adopted modular concept, the loads and associated load response and the remote handling.


Plasma boundary and first-wall diagnostics in ITER

Pitcher, C. S.*; Andrew, P.*; Barnsley, R.*; Bertalot, L.*; Counsell, G. G.*; Encheva, A.*; Feder, R. E.*; 波多江 仰紀; Johnson, D. W.*; Kim, J.*; et al.

Journal of Nuclear Materials, 415(Suppl.1), p.S1127 - S1132, 2011/08

 被引用回数:0 パーセンタイル:100(Materials Science, Multidisciplinary)

ITER plasma boundary and first-wall diagnostics are summarized in terms of their physical implementation and physics motivation. The challenge of extracting diagnostic signals while maintaining nuclear shielding is discussed, as well as the problems associated with high levels of erosion and redeposition.


Overview of high priority ITER diagnostic systems status

Walsh, M.*; Andrew, P.*; Barnsley, R.*; Bertalot, L.*; Boivin, R.*; Bora, D.*; Bouhamou, R.*; Ciattaglia, S.*; Costley, A. E.*; Counsell, G.*; et al.

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

The ITER device is currently under construction. To fulfil its mission, it will need a set of measurement systems. These systems will have to be robust and satisfy many requirements hitherto unexplored in Tokamaks. Typically, diagnostics occupy either a removable item called a port plug, or installed inside the machine as an intricate part of the overall construction. Limited space availability has meant that many systems have to be grouped together. Installation of the diagnostic systems has to be closely planned with the overall schedule. This paper will describe some of the challenges and systems that are currently being progressed.


Defining the infrared systems for ITER

Reichle, R.*; Andrew, P.*; Counsell, G.*; Drevon, J.-M.*; Encheva, A.*; Janeschitz, G.*; Johnson, D. W.*; 草間 義紀; Levesy, B.*; Martin, A.*; et al.

Review of Scientific Instruments, 81(10), p.10E135_1 - 10E135_5, 2010/10

 被引用回数:19 パーセンタイル:31.72(Instruments & Instrumentation)

ITER will have wide angle viewing systems and a divertor thermography diagnostic which shall provide infrared coverage of the divertor and large parts of the first wall surfaces with spatial and temporal resolution adequate for operational purposes and higher resolved details of the divertor and other areas for physics investigations. We propose specifications for each system such that they jointly respond to the requirements. Risk analysis driven priorities for future work concern mirror degradation, interfaces with other diagnostics, radiation damage to refractive optics, reflections and the development of calibration and measurements methods for varying optical and thermal target properties.


Recent progress on the development and analysis of the ITPA global H-mode confinement database

McDonald, D. C.*; Cordey, J. G.*; Thomsen, K.*; Kardaun, O. J. W. F.*; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; Stober, J.*; et al.

Nuclear Fusion, 47(3), p.147 - 174, 2007/03

 被引用回数:39 パーセンタイル:73.68(Physics, Fluids & Plasmas)

国際トカマク物理活動(ITPA)全体的Hモード閉じ込めデーターベースの第3版(DB3)に関し1994年から2004年の期間に行われた更新と解析について、この論文は記述する。エネルギー閉じ込め時間とその制御パラメータの巨視的データを、異なったサイズと形状の次の18装置から集めた。ASDEX, ASDEX Upgrade, C-Mod CoMPASS-D, DIII-D, JET, JFT-2M, JT-60U, MAST, NSTX, PBX-M, PDX, START, T-10, TCV, TdeV, TFTR及びUMAN-3M。このDB3データベースに基づき、幅広い物理研究が行われた。特に中心部と周辺部の振る舞いの分離,無次元解析、及びデータベースと1次元輸送コードとの比較に進展があった。データーベースは、ITERのような次期装置の閉じ込め特性の基盤を評価することを主要な目的としており、この論文でも解析結果を踏まえて次期装置を議論する。


Scaling of the energy confinement time with $$beta$$ and collisionality approaching ITER conditions

Cordey, J. G.*; Thomsen, K.*; Chudnovskiy, A.*; Kardaun, O. J. W. F.*; 滝塚 知典; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; et al.

Nuclear Fusion, 45(9), p.1078 - 1084, 2005/09

 被引用回数:47 パーセンタイル:15.91(Physics, Fluids & Plasmas)




波多江 仰紀; 谷塚 英一; Bassan, M.*; Vayakis, G.*; Walsh, M.*; 伊丹 潔

no journal, , 




谷塚 英一; 波多江 仰紀; 北澤 真一; Vayakis, G.*; Bassan, M.*; Walsh, M.*; 伊丹 潔

no journal, , 

ITERでは出力5J, パルス幅10ns以下のレーザーパルスを$$10^{9}$$回程度ビームダンプに入射されることが見込まれている。レーザーパルスを繰り返し入射する場合、被照射面の溶融に限らず、熱膨張・収縮を繰り返すことによる材料の疲労を回避することが、長寿命化に必須であり、ITERでの長期間の実験を可能にする。一方、周辺プラズマ計測で必要となる分解能を満たすためには、ビームの径を大きくしてエネルギー密度を下げることができないため、ビームダンプを特殊な形状(シェブロン型ビームダンプと呼ぶ)にすることにより、ビームエネルギーの吸収を分散させる構造を設計した。シェブロン型ビームダンプは、3か所に屈曲を持つ薄板が平行に多数並び、その間で反射を繰り返すことにより徐々にビームエネルギーを減衰させることができる。また、シェブロン型ビームダンプは、ITERでの熱負荷及び渦電流による応力に耐えることを示した。これらにより、トムソン散乱計測用レーザービームの終端に関するITERでの実現可能性を初めて示した。



谷塚 英一; 波多江 仰紀; Bassan, M.*; Vayakis, G.*; Walsh, M.*; 伊丹 潔

no journal, , 

レーザーは、ITER周辺トムソン散乱計測装置の開発における最重要技術の1つである。原子力機構では、ITER用に高出力の原型YAGレーザーの開発を進めている。当初、レーザーと同一の波長1064nmの光が、増幅器内部で光軸に対して垂直方向に往復してレーザーロッド内のエネルギーを損失させていたため、高出力化が困難となっていた。サマリウム添加ガラス製のフローチューブ使用により、この課題を克服し、ITERの目標を超える出力7.66J、繰り返し100Hzのレーザー開発に成功した。また、ITERでは、中性子, $$gamma$$線,ダストなどに光学機器がさらされるため、光学系の分光透過率が経時変化し、電子温度・密度に系統的な測定誤差が生じる。計測用YAGレーザーと同時にルビーレーザーを入射してトムソン散乱スペクトルを解析することによる分光透過率即時較正により、ITERで高精度な測定を常に行うことが可能であることを示した。さらに、これらの高出力レーザーは、ブランケットに据え付けたビームダンプにより、安全に吸収する。新方式のシェブロン型ビームダンプを設計し、ITERでの過酷な熱的・電磁的負荷に適合することを示した。



谷塚 英一; 波多江 仰紀; 竹山 茂治; Bassan, M.*; Vayakis, G.*; Walsh, M.*; 伊丹 潔

no journal, , 


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