Spectroscopic determination of impurity influx from localized surfaces

Behringer, K.; Summers, H. P.; Denne, B.; Forrest, M.; Stamp, M.

doi:10.1088/0741-3335/31/14/001

Cited by 170 publications

(129 citation statements)

References 34 publications

Supporting

Mentioning

126

Contrasting

Unclassified

Order By: Relevance

“…The gauges of interest are shown in Figure 4. In attached conditions, Γ D 0 at the divertor target can also be derived from the SBD measurements with the so-called S/XB method [33]: …”

Section: Comparison With Pressure Gaugesmentioning

confidence: 99%

Electron density determination in the divertor volume of ASDEX Upgrade via Stark broadening of the Balmer lines

Potzel

Dux

Müller

et al. 2014

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Abstract. In this article we present the development of a new diagnostic capable of determining the electron density in the divertor volume of ASDEX Upgrade. It is based on the spectroscopic measurement of the Stark broadening of the Balmer lines. In this work two approaches of calculating the Stark broadening, i.e. the unified theory and the model microfield method, are compared. It will be shown that both approaches yield similar results in the case of Balmer lines with high upper principal quantum numbers n. In addition, for typical ASDEX Upgrade parameters the influence of the Zeeman splitting on the high n Balmer lines is found to be negligible. Moreover, an assumption for the Doppler broadening of T n = 5 eV, which is the maximum FrankCondon dissociation energy of recycled neutrals, is sufficient. The initial electron density measurements performed using this method are found to be consistent with both Langmuir probe and pressure gauge data.

show abstract

“…The gauges of interest are shown in Figure 4. In attached conditions, Γ D 0 at the divertor target can also be derived from the SBD measurements with the so-called S/XB method [33]: …”

Section: Comparison With Pressure Gaugesmentioning

confidence: 99%

Electron density determination in the divertor volume of ASDEX Upgrade via Stark broadening of the Balmer lines

Potzel

Dux

Müller

et al. 2014

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…Passive spectroscopy was used for the characterisation of the erosion at the solid Be limiters using the inverse photon efficiency (the so called S/XB-value) [16]. In order to calculate an "effective" erosion yield the peak Be particle flux densities were normalized to the saturation current measured by Langmuir probes mounted on the reciprocating probe evaluated at the same radial position.…”

Section: Impurity Sources and Contentmentioning

confidence: 99%

First operation with the JET International Thermonuclear Experimental Reactor-like wall

et al. 2013

View full text Add to dashboard Cite

AbstrAct.To consolidate ITER design choices and prepare for its operation, JET has implemented ITER's plasma facing materials, namely Be at the main wall and W in the divertor. In addition, protection systems, diagnostics and the vertical stability control were upgraded and the heating capability of the neutral beams was increased to over 30 MW. First results confirm the expected benefits and the limitations of all metal plasma facing components (PFCs), but also yield understanding of operational issues directly relating to ITER. H-retention is lower by at least a factor of 10 in all operational scenarios compared to that with C PFCs. The lower C content (Section 1factor 10) have led to much lower radiation during the plasma burn-through phase eliminating breakdown failures.Similarly, the intrinsic radiation observed during disruptions is very low, leading to high power loads and to a slow current quench. Massive gas injection using a D 2 /Ar mixture restores levels of radiation and vessel forces similar to those of mitigated disruptions with the C wall. Dedicated L-H transition experiments indicate a reduced power threshold by 30%, a distinct minimum density and pronounced shape dependence. The L-mode density limit was found up to 30% higher than for C allowing stable detached divertor operation over a larger density range. Stable H-modes as well as the hybrid scenario could be only re-established when using gas puff levels of a few 10 21 es −1. On average the confinement is lower with the new PFCs, but nevertheless, H factors up to 1 (H-Mode) and 1.3 (at b N ≈ 3, hybrids) have been achieved withWconcentrationswell below themaximum acceptable level.

show abstract

“…The geometry of the views of different first-wall surfaces are further detailed in reference [12]. The inverse photon efficiency for the Mo-I line, also known as S/XB, is utilized to convert the Mo-I photon brightness to influx (per unit area) based on a standard formalism [5,26]. The specific Mo-I S/XB required for this study are provided in reference [27].…”

Section: Introductionmentioning

confidence: 99%