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Mencke JE, Moseev D, Salewski M, Larsen MR, Schmidt BS, Järleblad H, Lazerson S, Poloskei PZ, Ford O. Characterization of correlations of fast-ion H-alpha measurement volumes in Wendelstein 7-X by particle tracking. Rev Sci Instrum 2022; 93:123503. [PMID: 36586887 DOI: 10.1063/5.0128594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
This paper characterizes the correlation of simultaneous measurements with different fast-ion H-alpha (FIDA) spectroscopy sightlines on Wendelstein 7-X. Using a collisionless guiding-center code, it is shown that, for two investigated volumes in the bulk of the plasma, some regions of phase space are correlated and the magnetic configuration has little influence on this correlation. For the sightlines of the FIDA system, the correlation between these is explained well by the magnetic configuration. Sightlines with measurement volumes at the same spatial locations have the highest correlation, and sightlines with measurement volumes near the same flux surface but on different sides of the magnetic axis have a high correlation. The correlation between the blueshifted signal in the starting sightline and redshifted signal in the detection sightline is investigated, demonstrating that it is possible to investigate any finite interval of detection wavelengths. Due to the different shapes of the weight functions for the toroidal and oblique sightlines, the blue-redshift correlation is very different from the total-spectrum correlation. The correlation between the toroidal and oblique sightline fans is relatively much larger than the internal correlation in the oblique sightlines, which is however, much larger than the internal correlation in the toroidal sightlines. This is a result of the dependence of the weight functions on the angle between the sightline and magnetic field, illustrating how important it is for the FIDA sightlines to cover different angles with the magnetic field.
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Affiliation(s)
- Jacob Emil Mencke
- Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Dmitry Moseev
- Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - Mirko Salewski
- Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Mads Rud Larsen
- Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby, Denmark
| | | | - Henrik Järleblad
- Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Samuel Lazerson
- Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - Peter Zsolt Poloskei
- Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - Oliver Ford
- Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
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Ford OP, Vanó L, Alonso JA, Baldzuhn J, Beurskens MNA, Biedermann C, Bozhenkov SA, Fuchert G, Geiger B, Hartmann D, Jaspers RJE, Kappatou A, Langenberg A, Lazerson SA, McDermott RM, McNeely P, Neelis TWC, Pablant NA, Pasch E, Rust N, Schroeder R, Scott ER, Smith HM, Wegner T, Kunkel F, Wolf RC. Charge exchange recombination spectroscopy at Wendelstein 7-X. Rev Sci Instrum 2020; 91:023507. [PMID: 32113444 DOI: 10.1063/1.5132936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine diagnostic on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (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 normalized impurity density profiles under some typical plasma conditions.
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Affiliation(s)
- O P Ford
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - L Vanó
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - J A Alonso
- CIEMAT, Avenida Complutense, 40, 28040 Madrid, Spain
| | - J Baldzuhn
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - M N A Beurskens
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - C Biedermann
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - S A Bozhenkov
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - G Fuchert
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - B Geiger
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - D Hartmann
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - R J E Jaspers
- Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - A Kappatou
- Max-Planck Institut für Plasmaphysik, 85748 Garching, Germany
| | - A Langenberg
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - S A Lazerson
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - R M McDermott
- Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - P McNeely
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - T W C Neelis
- Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
| | - N A Pablant
- Princeton University Plasma Physics Laboratory, Princeton, New Jersey 08544, USA
| | - E Pasch
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - N Rust
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - R Schroeder
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - E R Scott
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - H M Smith
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Th Wegner
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - F Kunkel
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - R C Wolf
- Max-Planck Institut für Plasmaphysik, 17491 Greifswald, Germany
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Mertens P, Castaño Bardawil DA, Baross T, Biel W, Friese S, Hawkes N, Jaspers RJ, Kotov V, Krasikov Y, Krimmer A, Litnovsky A, Marchuk O, Neubauer O, Offermanns G, Panin A, Pokol G, Schrader M, Samm U. Status of the R&D activities to the design of an ITER core CXRS diagnostic system. Fusion Engineering and Design 2015. [DOI: 10.1016/j.fusengdes.2015.05.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pokol G, Zoletnik S, Dunai D, Marchuk O, Baross T, Erdei G, Grunda G, Kiss I, Kovacsik A, v.Hellermann M, Lischtschenko O, Biel W, Jaspers R, Durkut M. Fluctuation BES measurements with the ITER core CXRS prototype spectrometer. Fusion Engineering and Design 2013. [DOI: 10.1016/j.fusengdes.2013.02.171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kappatou A, Jaspers RJE, Delabie E, Marchuk O, Biel W, Jakobs MA. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration. Rev Sci Instrum 2012; 83:10D519. [PMID: 23126860 DOI: 10.1063/1.4732847] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.
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Affiliation(s)
- A Kappatou
- FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, 3430 BE Nieuwegein, The Netherlands.
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Uzun-Kaymak IU, Fonck RJ, McKee GR. Ultra-fast charge exchange spectroscopy for turbulent ion temperature fluctuation measurements on the DIII-D tokamak (invited). Rev Sci Instrum 2012; 83:10D526. [PMID: 23126866 DOI: 10.1063/1.4733548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A novel two-channel, high throughput, high efficiency spectrometer system has been developed to measure impurity ion temperature and toroidal velocity fluctuations associated with long-wavelength turbulence and other plasma instabilities. The spectrometer observes the emission of the n = 8-7 hydrogenic transition of C(+5) ions (λ(air) = 529.06 nm) resulting from charge exchange reactions between deuterium heating beams and intrinsic carbon. Novel features include a large, prism-coupled high-dispersion, volume-phase-holographic transmission grating and high-quantum efficiency, high-gain, low-noise avalanche photodiode detectors that sample emission at 1 MHz. This new diagnostic offers an order-of-magnitude increase in sensitivity compared to earlier ion thermal turbulence measurements. Increased sensitivity is crucial for obtaining enough photon statistics from plasmas with much less impurity content. The irreducible noise floor set by photon statistics sets the ultimate sensitivity to plasma fluctuations. Based on the measured photon flux levels for the entire spectral line, photon noise levels for T̃(i)/T(i) and Ṽ(i)/V(i) of ~1% are expected, while statistical averaging over long data records enables reduction in the detectable plasma fluctuation levels to values less than that. Broadband ion temperature fluctuations are observed to near 200 kHz in an L-mode discharge. Cross-correlation with the local beam emission spectroscopy measurements demonstrates a strong coupling of the density and temperature fields, and enables the cross-phase measurements between density and ion temperature fluctuations.
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Affiliation(s)
- I U Uzun-Kaymak
- Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706, USA.
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