Transport and deposition of injected hydrocarbons in plasma generator PSI-2

Bohmeyer, W.; Naujoks, D.; Маркин, А. А.; Arkhipov, Ievgen I.; Koch, B.; Schröder, Daniel; Fußmann, G.

doi:10.1016/j.jnucmat.2004.10.107

Cited by 17 publications

(19 citation statements)

References 4 publications

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“…This is in agreement with laboratory experiments of the chemical erosion of (soft, hydrogen-rich) a-C:H layers showing much higher erosion yields by thermal atomic hydrogen when compared to graphite [63]. The rate for reerosion of a-C:H layers by atomic hydrogen is temperature dependent as demonstrated in experiments in the PSI-2 simulator, while hydrocarbon deposition is not [64]. Thus, it is generally found that the combination of all the complex processes involved in the final deposition of hydrocarbons is such that there is a prevalence of hydrocarbon deposition at low surface temperatures and of erosion at high temperatures, as shown in Fig.…”

Section: Iv-2-c) Re-erosion By the Hydrogen Plasmasupporting

confidence: 89%

Plasma–wall interaction: Important ion induced surface processes and strategy of the EU Task Force

Roth¹,

Tsitrone²,

Loarte³

2007

Nuclear Instruments and Methods in Physics Research Section B:

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Abstract:In future thermo-nuclear fusion devices, such as ITER (International Thermonuclear Experimental Reactor), the interaction of the plasma with surrounding materials in the vacuum vessel constitutes one of the main remaining engineering problems. The choice of materials is a crucial point, which will determine issues such as the plasma facing components lifetime before refurbishment or the tritium inventory build up in the vessel, which should be limited for safety reasons. In order to tackle these issues, the European Task Force on Plasma wall interaction has been implemented in the frame of EFDA (European Fusion Agreement) in the fall 2002 with the aim "to provide ITER with information concerning lifetime-expectations of the divertor target plates and tritium inventory build-up rates in the foreseen starting configuration and to suggest improvements, including material changes, which could be implemented at an appropriate stage."The EU PWI TF brings together the efforts of 24 European associations in the following fields of investigation :• Material erosion and transport in tokamaks • Tritium inventory and removal • Transient heat loads on plasma facing components • Dust production and removal • Associated modelling and diagnostic development This paper will present the organisation of the EU PWI TF. It will provide examples for the multitude of surface processes in plasma-wall interaction and present the status of knowledge concerning material erosion and hydrogen retention for the choice of ITER materials (Beryllium, Carbon and Tungsten).

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Section: Iv-2-c) Re-erosion By the Hydrogen Plasmasupporting

confidence: 89%

Plasma–wall interaction: Important ion induced surface processes and strategy of the EU Task Force

Roth¹,

Tsitrone²,

Loarte³

2007

Nuclear Instruments and Methods in Physics Research Section B:

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“…Many machines are operating following this concept, such as the Plasma Interaction Surface Component Experimental Station (PISCES)-A [7] and -B [8] in UCSD (USA), PSI-2 [9] in IPP-Berlin, LENTA [10] in the Kurchatov Institute (Russia), the UMIST linear system (ULS) [11] in UMIST (UK), the Test Plasma by Direct Current (TPD)-II [12] in NIFS (Japan), Nagoya Divertor Simulator (NAGDIS)-I [13] and -II [14] in Nagoya Univ. (Japan) or TPDSHEET-IV [15] in Tokai Univ.…”

Section: Introductionmentioning

confidence: 99%

Diagnostics of Recombining Plasmas in Divertor Simulator MAP-II

Kado

Iida

Kajita

et al. 2005

J. Plasma Fusion Res.

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Atomic and molecular processes in volumetric recombination phenomena relevant to divertor detachment are investigated in a divertor simulator MAP (Material and Plasma) -II. In the recombining plasmas, quantitative measurements of parameters, especially using a Langmuir probe, are diffi cult, so that the development of alternative diagnostics is important. Recombination can be induced in He plasma by puffi ng of He or H 2 . In the He puffi ng case, the Rydberg spectra show an electron temperature of lower than 0.1 eV, while in the H 2 puffi ng case, the Rydberg spectra disappear even though the reduction of the ion fl ux is apparent, showing that another type of recombination occurs. Negative hydrogen ions are observed in the peripheral region of the plasma column.

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“…1.00E-8 From our previous investigations [2] it could also be inferred that practically all carbon atoms injected into the plasma chamber, either as ethylene (C 2 H 4 ) or CH 4 , are retained inside the vessel, most likely bound in a-C:H layers on the inner walls of vessel. We first used C 2 H 2 (acetylene) having the benefit that the same amount of carbon and hydrogen is injected.…”

Section: Resultsmentioning

confidence: 87%

“…From earlier experiments [2] it is known that the degree of decomposition of the injected C x H y molecules strongly depends on electron density. Nevertheless, the threshold density for decomposition is relatively low.…”

Section: Resultsmentioning

confidence: 99%

Study Of The Gas Balance By Injection Of Hydrocarbons Into The Plasma Simulator PSI 2

Bohmeyer

Маркин

Koch

et al. 2006

AIP Conference Proceedings

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Abstract. The stationary plasma of the plasma generator PSI 2 is used to study the gas balance of hydrocarbons and hydrogen by means of mass spectrometers. For this purpose H 2 , acetylene and ethylene are injected into argon and hydrogen plasmas. Several mono-layers of a-C:H are formed after only a few minutes of injection. It is found that hydrogenation of the hydrocarbon layers is strongly influenced by the hydrocarbon species injected previously. Furthermore, time constants of more than 1000 s for achieving stationary conditions are identified in some cases. The H/C ratio of the hydrocarbon layers is found to vary from about 1 to 1.4 for argon and hydrogen plasmas, respectively. PACS :81.05, 91.15-z , 52.40 Hf

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Transport and deposition of injected hydrocarbons in plasma generator PSI-2

Cited by 17 publications

References 4 publications

Plasma–wall interaction: Important ion induced surface processes and strategy of the EU Task Force

Plasma–wall interaction: Important ion induced surface processes and strategy of the EU Task Force

Diagnostics of Recombining Plasmas in Divertor Simulator MAP-II

Study Of The Gas Balance By Injection Of Hydrocarbons Into The Plasma Simulator PSI 2

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