ECE Diagnostic for the initial Operation of Wendelstein 7-X

Hirsch, M.; Höfel, U.; Oosterbeek, J.W.; Chaudhary, N.; Geiger, J.; Hartfuß, H. J.; Kasparek, W.; Marushchenko, N. B.; Plaum, B.; Stange, T.; Svensson, J.; Takahashi, Hayato; Wágner, D.; Weir, G.; Wolf, R. C.

doi:10.1051/epjconf/201920303007

Cited by 28 publications

(25 citation statements)

References 12 publications

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“…From the beginning of the first phase of W7-X operation, the electron kinetic information has been well diagnosed by Thomson Scattering 5 , Electron Cyclotron Emission 6 and a dispersion interferometer 7 .…”

Section: Introductionmentioning

confidence: 99%

Charge exchange recombination spectroscopy at Wendelstein 7-X

Ford

Vanó

Alonso

et al. 2020

Review of Scientific Instruments

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The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine diagnostic on almost all major high temperature fusion experimental devices. For the optimised stellarator W7-X, a highly flexible and extensive CXRS diagnostic has been built to provide high-resolution local measurements of several important plasma parameters using the recently commissioned neutral beam heating. This paper outlines the design specifics of the W7-X CXRS system and gives examples of the initial results obtained including typical ion temperature profiles for several common heating scenarios, toroidal flow and radial electric field derived from velocity measurements, beam attenuation via beam emission spectra and finally, normalised impurity density profiles under some typical plasma conditions.

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Section: Introductionmentioning

confidence: 99%

Charge exchange recombination spectroscopy at Wendelstein 7-X

Ford

Vanó

Alonso

et al. 2020

Review of Scientific Instruments

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“…In order to compare the level of anomalous electron heat transport in each magnetic configuration, and to assess the impact of the magnetic configuration on the anomalous electron heat transport, it is necessary to match the kinetic profiles and their normalized gradients between configurations. The electron temperature profile in W7-X is measured using a combination of Thomson scattering [14,15] and electron cyclotron emission (ECE) radiometry [16,17] diagnostics. The line-average plasma density is measured by a single-channel interferometer [18], and the plasma density profile is measured through Thomson scattering.…”

Section: Matched Profile Experiments In Three Magnetic Configurationsmentioning

confidence: 99%

Heat pulse propagation and anomalous electron heat transport measurements on the optimized stellarator W7-X

et al. 2021

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The optimized stellarator Wendelstein 7-X (W7-X) is designed to have an approximately quasi-isodynamic magnetic configuration with reduced neoclassical transport in comparison to a classical stellarator, and turbulent transport is expected to be a significant source of anomalous heat transport across the plasma minor radius. The ion temperature gradient driven mode and the trapped electron mode (TEM) are thought to be responsible for the ion-scale turbulence in W7-X plasmas with volume averaged pressure below 1%. In this work, the electron temperature gradient driven turbulence is shown to be a good candidate for the explanation of the observed electron heat flux, in the inner plasma region where the density gradient is weak (in the outer region, a relatively stronger density gradient would drive additional TEM turbulence). The experimental electron heat transport measured during electron cyclotron resonant heating power and plasma density scans is compared to neoclassical predictions, and the stiffness in the electron heat transport measured during transient transport experiments is presented in three common magnetic configurations of W7-X. In low-β plasma discharges, the stiffness in the electron heat flux, quantified by the ratio of the heat pulse to power balance diffusivity, χ HP e /χ PB e , is measured to be less than 2, and trend downwards with increasing collisionality.

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“…8) delivers the electron temperature Te, but only up to the ncut-off -density due to the increasing reflectivity of the plasma. [7] Fig. 8 ECE-measuring at W7-X…”

Section: Electron Temperaturementioning

confidence: 99%

The fast Interlock system of W7-X – First experience

Vilbrandt

Schacht

Herbst

et al. 2020

Fusion Engineering and Design

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This paper focuses on the design, installation and test of the first version of the Fast Interlock System (FIS) of W7-X. The structure of the system and the basic components including some safety-relevant plasma diagnostics are described. The very first practical experiences with the FIS have been gained during the operation phase 1.2b in summer 2018. Next to the proof of a satisfactory reaction, scalability and operability, the focus also was on the assessment of the reaction times of the core system and the various safety-relevant plasma diagnostics during several experimental situations. A couple of planned measures to improve and extend the FIS will be presented in this paper.

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ECE Diagnostic for the initial Operation of Wendelstein 7-X

Cited by 28 publications

References 12 publications

Charge exchange recombination spectroscopy at Wendelstein 7-X

Charge exchange recombination spectroscopy at Wendelstein 7-X

Heat pulse propagation and anomalous electron heat transport measurements on the optimized stellarator W7-X

The fast Interlock system of W7-X – First experience

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