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Barbui T, Chellaï O, Delgado-Aparicio LF, Peysson Y, Stratton B, Dumont R, Hill KW, Pablant NA. Spatial calibration and synthetic diagnostic of a multi-energy hard x-ray camera at WEST tokamak. Rev Sci Instrum 2022; 93:103508. [PMID: 36319367 DOI: 10.1063/5.0101794] [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: 06/03/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
WEST (tungsten environment in steady-state tokamak) is starting operation for the first time with a water-cooled full tungsten divertor, enabling long pulse operation. Heating is provided by radiofrequency systems, including lower hybrid current drive (LHCD). In this context, a compact multi-energy hard x-ray camera has been installed for energy and space-resolved measurements of the electron temperature, the fast electron tail density produced by LHCD and runaway electrons, and the beam-target emission of tungsten at the target due to fast electron losses interacting with the divertor plates. The diagnostic is a pinhole camera based on a 2D pixel array detector (Pilatus 3 CdTe CMOS Hybrid-Pixel detector produced by DECTRIS). The novelty of this diagnostic technique is the detector's capability of adjusting the threshold energy at pixel level. This innovation provides great flexibility in the energy configuration, allowing simultaneous space and energy-resolved x-ray measurements. This contribution details two important steps in the preparation of the diagnostic operation. First, the in-vessel spatial calibration that was carried out with a radioactive source. Second, the synthetic diagnostic is obtained by the suite of codes ALOHA/C3PO/LUKE/R5-X2, which simulates LH wave propagation and absorption, as well as the fast electron bremsstrahlung production.
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Affiliation(s)
- T Barbui
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - O Chellaï
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | | | - Y Peysson
- IRFM - CEA Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - B Stratton
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R Dumont
- IRFM - CEA Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - K W Hill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - N A Pablant
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
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Manke F, Baquero-Ruiz M, Furno I, Chellaï O, Fasoli A, Ricci P. Truncated Lévy motion through path integrals and applications to nondiffusive suprathermal ion transport. Phys Rev E 2019; 100:052122. [PMID: 31869979 DOI: 10.1103/physreve.100.052122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Indexed: 11/07/2022]
Abstract
Fractional Levy motion has been derived from its generalized Langevin equation via path integrals in earlier works and has since proven to be a useful model for nonlocal and non-Markovian processes, especially in the context of nondiffusive transport. Here, we generalize the approach to treat tempered Lévy distributions and derive the propagator and diffusion equation of truncated asymmetrical fractional Levy motion via path integrals. The model now recovers exponentially tempered tails above a chosen scale in the propagator, and therefore finite moments at all orders. Concise analytical expressions for its variance, skewness, and kurtosis are derived as a function of time. We then illustrate the versatility of this model by applying it to simulations of the turbulent transport of fast ions in the TORPEX basic plasma device.
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Affiliation(s)
- F Manke
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - M Baquero-Ruiz
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Chellaï
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Ricci
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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Manke F, Baquero-Ruiz M, Furno I, Chellaï O, Fasoli A, Ricci P. Time intermittency in nondiffusive transport regimes of suprathermal ions in turbulent plasmas. Phys Rev E 2019; 99:053208. [PMID: 31212579 DOI: 10.1103/physreve.99.053208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Indexed: 06/09/2023]
Abstract
Intermittent phenomena have long been studied in the context of nondiffusive transport across a variety of fields. In the TORPEX device, the cross-field spreading of an injected suprathermal ion beam by electrostatic plasma turbulence can access different nondiffusive transport regimes. A comprehensive set of suprathermal ion time series has been acquired, and time intermittency quantified by their skewness. Values distinctly above background level are found across all observed transport regimes. Intermittency tends to increase toward quasi- and superdiffusion and for longer propagation times of the suprathermal ions. The specific prevalence of intermittency is determined by the meandering motion of the instantaneous ion beam. We demonstrate the effectiveness of an analytical model developed to predict local intermittency from the time-average beam. This model might thus be of direct interest for similar systems, e.g., in beam physics, or meandering flux-rope models for solar energetic particle propagation. More generally, it illustrates the importance of identifying the system-specific sources of time-intermittent behavior when analyzing nondiffusive transport.
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Affiliation(s)
- F Manke
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - M Baquero-Ruiz
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Chellaï
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Ricci
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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Baquero-Ruiz M, Alberti S, Chellaï O, Furno I, Goodman T, Manke F, Micheletti P, Plyushchev G, Skrivervik AK. Optically isolated millimeter-wave detector for the Toroidal Plasma Experiment. Rev Sci Instrum 2018; 89:124702. [PMID: 30599624 DOI: 10.1063/1.5053991] [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: 08/28/2018] [Accepted: 11/13/2018] [Indexed: 06/09/2023]
Abstract
We have designed and built an optically isolated millimeter-wave detection system to prevent interference from a nearby, powerful, 2.45 GHz microwave source in millimeter-wave propagation experiments in the TORoroidal Plasma EXperiment (TORPEX). A series of tests demonstrates excellent system noise immunity and the ability to observe effects that cannot be resolved in a setup using a bare Schottky diode detector.
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Affiliation(s)
- M Baquero-Ruiz
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - S Alberti
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Chellaï
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - T Goodman
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - F Manke
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Micheletti
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - G Plyushchev
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A K Skrivervik
- École Polytechnique Fédérale de Lausanne (EPFL), Microwaves and Antennas Group (MAG), CH-1015 Lausanne, Switzerland
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Chellaï O, Alberti S, Baquero-Ruiz M, Furno I, Goodman T, Manke F, Plyushchev G, Guidi L, Koehn A, Maj O, Poli E, Hizanidis K, Figini L, Ricci D. Millimeter-Wave Beam Scattering by Field-Aligned Blobs in Simple Magnetized Toroidal Plasmas. Phys Rev Lett 2018; 120:105001. [PMID: 29570337 DOI: 10.1103/physrevlett.120.105001] [Citation(s) in RCA: 2] [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] [Received: 11/14/2017] [Indexed: 06/08/2023]
Abstract
The first direct experimental measurements of the scattering of a millimeter-wave beam by plasma blobs in a simple magnetized torus are reported. The wavelength of the beam is comparable to the characteristic size of the blob. In situ Langmuir probe measurements show that fluctuations of the electron density induce correlated fluctuations of the transmitted power. A first-principles full-wave model, using conditionally sampled 2D electron density profiles, predicts fluctuations of the millimeter-wave power that are in agreement with experiments.
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Affiliation(s)
- O Chellaï
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - S Alberti
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - M Baquero-Ruiz
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - I Furno
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - T Goodman
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - F Manke
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - G Plyushchev
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - L Guidi
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - A Koehn
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
- Institute of Interfacial Process Engineering and Plasma Technology, University of Stuttgart, 70174 Stuttgart, Germany
| | - O Maj
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - E Poli
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - K Hizanidis
- National Technical University of Athens, 106 82 Athens, Greece
| | - L Figini
- Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, 20125 Milan, Italy
| | - D Ricci
- Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, 20125 Milan, Italy
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Chellaï O, Alberti S, Furno I, Goodman T, Koehn A, Figini L, Ricci D, Hizanidis L, Papagiannis P, Tsironis C. Experimental study of high power mm-waves scattering by plasma turbulence in TCV plasmas. EPJ Web Conf 2017. [DOI: 10.1051/epjconf/201715703008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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