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Recent experiments with the European 1MW, 170GHz industrial CW and short-pulse gyrotrons for ITER. FUSION ENGINEERING AND DESIGN 2019. [DOI: 10.1016/j.fusengdes.2018.12.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:023501. [PMID: 30831775 DOI: 10.1063/1.5048361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X.
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Collective Thomson scattering diagnostic at Wendelstein 7-X. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013503. [PMID: 30709181 DOI: 10.1063/1.5050193] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
A Collective Thomson Scattering (CTS) diagnostic is installed at Wendelstein 7-X for ion temperature measurements in the plasma core. The diagnostic utilizes 140 GHz gyrotrons usually used for electron cyclotron resonance heating (ECRH) as a source of probing radiation. The CTS diagnostic uses a quasi-optical transmission line covering a distance of over 40 m. The transmission line is shared between the ECRH system and the CTS diagnostic. Here we elaborate on the design, installation, and alignment of the CTS diagnostic and present the first measurements at Wendelstein 7-X.
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Phased array Doppler reflectometry at Wendelstein 7-X. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10H115. [PMID: 30399932 DOI: 10.1063/1.5039287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/14/2018] [Indexed: 06/08/2023]
Abstract
A passive phased array Doppler reflectometry system has recently been installed in the Wendelstein-7X stellarator. In contrast to conventional Doppler reflectometry systems, the microwave beam can be steered on short time scales in the measurement plane perpendicular to the magnetic field in the range of ±25° without mechanical steering components. This paper characterizes the design and properties of the phased array antenna system and presents the first measurement results from the latest OP1.2a campaign.
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Prediction of ohmic losses in miter bend polarizers. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818701023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Remote-Steering Antennas for 140 GHz Electron Cyclotron Heating of the Stellarator W7-X. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714704004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Electron Cyclotron Resonance Heating Experiments in the Wendelstein VII-A Stellarator. ACTA ACUST UNITED AC 2017. [DOI: 10.13182/fst85-a24543] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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High-Power Tests of a Remote-Steering Antenna at 140 GHz. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst06-a1216] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Power Combination of Two 140-GHz Gyrotrons and Fast Switching of the Combined Beam. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst09-a4050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Operation Experience with the ASDEX Upgrade ECRH System. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst09-a4051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Electron Cyclotron Heating for W7-X: Physics and Technology. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst07-a1508] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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ECRH for W7-X: Transmission Losses of High-Power 140-GHz Wave Beams. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst09-a4049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Fast Switching and Power Combination of High-Power Electron Cyclotron Wave Beams: Principles, Numerical Results, and Experiments. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst07-a1507] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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High-Power Performance of a Resonant Diplexer for Advanced ECRH. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst11-a11738] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Magnetic Island Localization for NTM Control by ECE Viewed Along the Same Optical Path of the ECCD Beam. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst09-a4071] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Optics for electron cyclotron resonance heating and collective Thomson scattering at the stellarator W7-X. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714901013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Millimetre wave attenuation of prototype diagnostic components for the ITER bolometers. FUSION ENGINEERING AND DESIGN 2015. [DOI: 10.1016/j.fusengdes.2015.06.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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24
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Development of Resonant Diplexers for high-power ECRH – Status, Applications, Plans. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158704010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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High power ECRH and ECCD in moderately collisional ASDEX Upgrade Hmodes and status of EC system upgrade. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158702004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Research and Development of 2-frequency (110/138 GHz) FADIS for JT-60SA ECHCD system. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158704009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158704012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Alternative optical concept for electron cyclotron emission imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D802. [PMID: 25430215 DOI: 10.1063/1.4884902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.
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Status of the diagnostics development for the first operation phase of the stellarator Wendelstein 7-X. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D818. [PMID: 25430231 DOI: 10.1063/1.4889905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infrared (IR) optical diagnostics are described.
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Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123203006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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ECRH on ASDEX Upgrade - System Status, Feed-Back Control, Plasma Physics Results -. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123202011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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In-situ characterization of spurious modes in HE 11transmission lines with a 5-port coupler. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123204010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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A remotely steered millimetre wave launcher for electron cyclotron heating and current drive on ITER. FUSION ENGINEERING AND DESIGN 2010. [DOI: 10.1016/j.fusengdes.2009.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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43
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Tests of a 105Ghz prototype diplexer–combiner based on square corrugated waveguide. FUSION ENGINEERING AND DESIGN 2009. [DOI: 10.1016/j.fusengdes.2008.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Electron-Bernstein-wave current drive in an overdense plasma at the Wendelstein 7-AS stellarator. PHYSICAL REVIEW LETTERS 2003; 90:075003. [PMID: 12633236 DOI: 10.1103/physrevlett.90.075003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2002] [Indexed: 05/24/2023]
Abstract
Electron-Bernstein-wave (EBW) current drive in an overdense plasma was demonstrated at the Wendelstein 7-AS stellarator for the first time. The EBWs were generated by O-X-B mode conversion. The relatively high current drive efficiency was consistent with theoretical predictions. The experiments provided first investigations of EBW phase space interaction for wave refractive indices much larger than unity.
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Performance of the 140 GHz prototype transmission system for ECRH on the stellarator W7-X. FUSION ENGINEERING AND DESIGN 2001. [DOI: 10.1016/s0920-3796(01)00271-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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