Hydrocarbon injection for quantification of chemical erosion yields in tokamaks

Brezinsek, S.; Pospieszczyk, A.; Borodin, D.; Stamp, M.; Pugno, R.; McLean, A.G.; Fantz, U.; Manhard, A.; Kallenbach, A.; Brooks, N.H.; Groth, M.; Mertens, Ph.; Philipps, V.; Samm, U.

doi:10.1016/j.jnucmat.2007.01.190

Cited by 60 publications

(78 citation statements)

References 22 publications

(23 reference statements)

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“…The impurity release behaviour is to a certain extent similar to the sputtering of carbon from graphite with observation of C + (CII emission), representing physical and chemical erosion, and CD (CD A-X band emission), reflecting solely the chemical erosion with predominantly methane release and break-up into CD [19]. Also the chemical sputtering of graphite vanishes at higher surface temperatures as measured in TEXTOR under comparable edge plasma conditions as in JET [19] and analytically described in [23].…”

Section: Comparison With the Composition Of The Total C Sputtering Yieldmentioning

confidence: 57%

“…Also the chemical sputtering of graphite vanishes at higher surface temperatures as measured in TEXTOR under comparable edge plasma conditions as in JET [19] and analytically described in [23]. However, the chemical sputtering process and the energy of the radicals produced is different in the case of Be and C, whereas the latter is thermally released.…”

Section: Comparison With the Composition Of The Total C Sputtering Yieldmentioning

confidence: 70%

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Study of physical and chemical assisted physical sputtering of beryllium in the JET ITER-like wall

Brezinsek¹,

Stamp²,

Nishijima³

et al. 2014

Nucl. Fusion

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Abstract:The effective sputtering yield of Be (Y tot Be ) was determined in-situ by emission spectroscopy of low ionising Be as function of the deuteron impact energy (E in = 25 − 175eV ) and Be surface temperature ( ). The later mechanism has been clearly identified by the appearance of BeD A-X emission and quantified in cause of a temperature dependence at which the BeD practically vanishes at highest observed Be limiter temperatures. The recorded T surf dependence, obtained in a series of 34 identical discharges with ratch-up of T surf by plasma impact and inertial cooling after the discharge, revealed that the reduction of BeD is correlated with an increase of D 2 emission. The release mechanism of deuterium in the Be interaction layer is exchanged under otherwise constant recycling flux conditions at the limiter. The reduction of Y chem Be with T surf is also correlated to the reduction of the Be content in the core plasma providing information on the total source strength and Be screening. The chemical assisted physical sputtering, always present at the nominal limiter pre-heating temperature of T surf = 200 • C, is associated with an additional sputtering channel with respect to ordinary physical sputtering which is surface temperature independent. These JET experiments in limiter configuration are used to benchmark the ERO code and verify ITER first wall erosion prediction. The ERO code overestimates the observed Be sputtering in JET by a factor of about 2.5 which can be transferred to ITER predictions and prolong the expected lifetime of first wall elements.

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Section: Comparison With the Composition Of The Total C Sputtering Yieldmentioning

confidence: 57%

Section: Comparison With the Composition Of The Total C Sputtering Yieldmentioning

confidence: 70%

Study of physical and chemical assisted physical sputtering of beryllium in the JET ITER-like wall

Brezinsek¹,

Stamp²,

Nishijima³

et al. 2014

Nucl. Fusion

Self Cite

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“…The tile embedded LP (KY4D [6]) and Paschen/Balmer recombination spectroscopy (KT3) provide T e and n e , radiated powers are obtained with the divertor bolometry system (KB5 [7]) and the divertor neutral density n D is supplied by a sub-divertor neutral pressure gauge (KT5P). In-situ the hydrocarbon flux Γ CD and the incident particle fluxΓ D are obtained with the aid of divertor spectroscopy (KS3 [4]) and local CD 4 injection (GIM14). Figure 1a illustrates the detection coverage of the toroidally separated diagnostics in one toroidal plane of the divertor.…”

Section: Experimental Set-up and Plasma Scenariomentioning

confidence: 99%

“…Chemical sputtering can be described as a function of ion energy, ion flux and surface temperature [3], though uncertainties with respect to data interpretation and extrapolation to detached plasma conditions exist. Recent experiments in Asdex-Upgrade and DIII-D at low surface temperatures (T surface ≅ 350K) showed a reduction of the intrinsic hydrocarbon flux and the chemical sputtering yield under detached conditions in comparison to attached conditions in high density plasmas [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Quantifcation of the chemical sputtering is done in-situ with spectroscopy on the hydrocarbon breakup product CD in combination with local CD 4 injection [4] into the near outboard SOL through a single injection module. This experiment focuses on both the exploitation of steady-state detached divertor operation with carbon PFCs and the determi-nation of the carbon erosion under these conditions.…”

Section: Introductionmentioning

confidence: 99%

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