Influence of in-situ carbon coatings on window materials in fusion-experimental devices

Okazaki, Kiyohiko; Oyama, Hitoshi; Ishibe, Yukio; Kato, Shigekí; Sakamoto, Yuichi; Amemiya, Susumu; Masuda, Toshio; Tsurita, Yukio; Hori, Yoichiro; Akaishi, K.; Kawahata, K.; Noda, N.

doi:10.1016/0022-3115(87)90441-7

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…In situ optical measurement of the Mo deposition flux dep Mo is done at the same port. The thickness of the carbon deposited on sapphire substrate has been ex situ measured by the same transmission method during 3.5 h carbonization, 0.5 h D 2 cleaning and 50 tokamak shots in JIPP tokamak [27], and the in situ reflectometer technique has been developed to apply for TEXTOR [28]. Here we evaluate the transmission of the observed H α intensity at this port, which was decayed in time, although H α intensities at other ports could be kept constant, because of no contamination of the viewing window due to the ∼1 m distance from the plasma.…”

Section: Metal Source Profile and In Situ Measurement Of Mo Depositio...mentioning

confidence: 99%

Steady-state tokamak operation, ITB transition and sustainment and ECCD experiments in TRIAM-1M

et al. 2005

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Experiments aiming at 'day long operation at high performance' have been carried out in TRIAM-1M. The record value of the discharge duration was updated to 5 h and 16 min. Steady-state tokamak operation is studied under the localized plasma wall interaction conditions. The distributions of the heat load, the particle recycling flux and impurity source are investigated to understand the co-deposition and wall pumping. The formation and sustainment of an internal transport barrier (ITB) in enhanced current drive mode has been investigated by controlling the lower hybrid driven current profile by changing the phase spectrum. An ITER relevant remote steering antenna for electron cyclotron wave injection was installed and a relativistic Doppler resonance of the oblique propagating extraordinary wave with energetic electrons driven by lower hybrid waves was studied.

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Section: Metal Source Profile and In Situ Measurement Of Mo Depositio...mentioning

confidence: 99%

Steady-state tokamak operation, ITB transition and sustainment and ECCD experiments in TRIAM-1M

et al. 2005

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“…The measured spectral transmission losses of a TFTR window [238] were found to be very similar to samples coated in laboratory glow [253] and ECR discharges in H 2 /CH 4 gas mixtures. Based on windows used in JT60-U during 1992-1995, a simple polynomial description for the wavelength dependent attenuation by a film of thickness d has empirically been derived [246].…”

Section: Contamination Of Diagnostic Windowsmentioning

confidence: 71%

“…Detailed investigations particularly into the chromatic transmission of predominantly hydrocarbon coated windows have been undertaken in the field of Thomson scattering diagnostics since the wavelength dependence leads to significant errors in derived temperatures, but of course also in density measurements [238,246]. The measured spectral transmission losses of a TFTR window [238] were found to be very similar to samples coated in laboratory glow [253] and ECR discharges in H 2 /CH 4 gas mixtures. Based on windows used in JT60-U during 1992-1995, a simple polynomial description for the wavelength dependent attenuation by a film of thickness d has empirically been derived [246].…”

Section: Contamination Of Diagnostic Windowsmentioning

confidence: 99%

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Diagnostics for steady state plasmas

Hartfuß¹,

König²,

Werner³

2006

Plasma Phys. Control. Fusion

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Problems related to the development of diagnostics for steady state fusion plasma experiments are being discussed. The paper concentrates on those necessities already appearing in nowadays non-burning plasma fusion experiments when extending pulse lengths beyond 10 s, i.e. thermal load, erosion, deposition, and long-time signal integration in magnetic diagnostics. Problems arising from high power ECRH under conditions of incomplete absorption are outlined. Individual standard diagnostic systems are discussed to identify their specific problems as well as the opportunities connected with long pulse operation. Burning plasma experiments characterized by intense n-and g-radiation are briefly reviewed for reasons of completeness, dealing with radiation induced processes in windows, fibres, cables, and mirrors. Methods of data handling, real time monitoring, and plasma control are outlined. Index

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Effect of changes in viewing window transmission on high-temperature Thomson scattering data

Mcneill

1990

Review of Scientific Instruments

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Unmonitored changes in the transmission of viewing windows owing to deposited films can produce errors in Thomson scattering temperature measurements. This effect is illustrated by a recent run on the Tokamak Fusion Test Reactor (TFTR) where apparent errors of over 25% in peak temperatures of 9 keV owing to carbon films were noted. Since coatings can also be removed by hydrogen discharges, the transmission of a window may change with time, resulting in variable errors in the temperature. It is proposed that these changes be monitored by calibration in situ with the aid of a low-pressure hydrogen glow discharge.

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Influence of in-situ carbon coatings on window materials in fusion-experimental devices

Cited by 3 publications

References 6 publications

Steady-state tokamak operation, ITB transition and sustainment and ECCD experiments in TRIAM-1M

Steady-state tokamak operation, ITB transition and sustainment and ECCD experiments in TRIAM-1M

Diagnostics for steady state plasmas

Effect of changes in viewing window transmission on high-temperature Thomson scattering data

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