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8.56-GHz quasi-optical launcher system with incident-mode selectivity on the QUEST spherical tokamak. FUSION ENGINEERING AND DESIGN 2023. [DOI: 10.1016/j.fusengdes.2023.113479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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2
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Conceptual design of a heavy ion beam probe for the QUEST spherical tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113516. [PMID: 36461548 DOI: 10.1063/5.0101770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/11/2022] [Indexed: 06/17/2023]
Abstract
A heavy ion beam probe (HIBP) has been designed for the QUEST spherical tokamak to measure plasma turbulence and the profiles of electric potential profiles. Using a cesium ion beam with an energy of several 10 keV, the observable region covers most of the upper half of the plasma. Although the probe beam is deflected by the poloidal magnetic field produced by plasma current and poloidal coil currents, it can be detected under plasma current up to 150 kA by modifying the trajectories with two electrostatic sweepers. According to the numerical estimation of the intensity of the detected beam, sufficient signal intensity for measuring plasma turbulence can be obtained over almost the measurable area when the electron density is up to 1 × 1019 m-3, which is larger than the cut-off density of electron cyclotron heating in QUEST. The performance of the designed HIBP is sufficient to explore the mechanisms of heat and particle transport in magnetically confined plasmas, including the influence of plasma wall interactions, which is a goal of the QUEST project.
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Adaptive Capon beamforming for lensless electron cyclotron emission imaging with high spatial resolution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103531. [PMID: 36319327 DOI: 10.1063/5.0101632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Electron cyclotron emission (ECE) imaging diagnostics incorporating a lensless approach have been developed for measurements involving active spatial selectivity and direction-of-arrival estimation. The Capon method for adaptive-array analysis was proposed to improve the spatial resolution of the two-dimensional ECE imaging technique. Broadband noise source emissions were used to simulate the ECE to verify the practical effectiveness of the Capon method in the ECE imaging. Multiple noise source emission positions were properly estimated with a high spatial resolution using the Capon method.
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Overview of recent progress on steady state operation of all-metal plasma facing wall device QUEST. NUCLEAR MATERIALS AND ENERGY 2021. [DOI: 10.1016/j.nme.2021.101013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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Measurement of axial phase difference of density fluctuations owing to spontaneously excited waves by using microwave reflectometer on GAMMA 10/PDX. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:053506. [PMID: 34243319 DOI: 10.1063/5.0043821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/14/2021] [Indexed: 06/13/2023]
Abstract
In the GAMMA 10/PDX tandem mirror, plasma with strong ion-temperature anisotropy is produced by using the ion cyclotron range of frequency waves. This anisotropy of ion temperature causes several Alfvén-Ion-Cyclotron (AIC) waves to spontaneously excite in the frequency range just below the ion cyclotron frequency. In addition, difference-frequency (DF) waves are excited in the radial inner region of the plasma by wave-wave coupling among the AIC waves. The radial density profiles were measured at multi-axial positions using a frequency-modulation reflectometer with an axial array of microwave antennas, and an axial variation of the density was found to be significant. In addition, a relative phase difference of the DF wave between axially separated two points was first obtained by finely choosing the probing frequency of the reflectometers with a maximum coherence used as a measure, indicating that the DF wave is a propagating wave, while the pump AIC waves are standing waves in the axial region of measurement.
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6
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Toroidal flow measurements of impurity ions in QUEST ECH plasmas using multiple viewing chords emission spectroscopy. NUCLEAR MATERIALS AND ENERGY 2021. [DOI: 10.1016/j.nme.2021.100905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Investigation of radial distribution of atomic hydrogen flux to the plasma facing components in steady state discharges in QUEST tokamak. NUCLEAR MATERIALS AND ENERGY 2021. [DOI: 10.1016/j.nme.2020.100872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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High voltage electrical system of 8.56 GHz CW klystron for electron cyclotron heating on QUEST spherical tokamak. FUSION ENGINEERING AND DESIGN 2019. [DOI: 10.1016/j.fusengdes.2019.04.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Quasi-optical polarizer system for ECHCD experiments in the QUEST. FUSION ENGINEERING AND DESIGN 2019. [DOI: 10.1016/j.fusengdes.2019.02.099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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12
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First Results and Future Research Plan of Divertor Simulation Experiments Using D-Module in the End-Cell of the GAMMA 10/PDX Tandem Mirror. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst13-a16881] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Radial Transport of High-Energy Ions Caused by Low-Frequency Fluctuations in the GAMMA 10 Tandem Mirror. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst11-a11583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Ion-Cyclotron Resonance Heating Experiment in the Quadruple Minimum-B Field on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst11-a11625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Recent Results of Divertor Simulation Experiments Using D-Module in the GAMMA 10/PDX Tandem Mirror. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-882] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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High-Density Plasma Production in the GAMMA 10 Central Cell with ICRF Heating on Both Anchor Cells. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-890] [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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17
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Extension of Operational Regimes with ICRF Heating on GAMMA 10/PDX. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Analysis of Wave Excitation of the Phase-Control ICRF Antennas with Three-Dimensional Full Wave Code on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Multi-point measurement using two-channel reflectometer with antenna switching for study of high-frequency fluctuations in GAMMA 10. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:033504. [PMID: 28372363 DOI: 10.1063/1.4978323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A two-channel microwave reflectometer system with fast microwave antenna switching capability was developed and applied to the GAMMA 10 tandem mirror device to study high-frequency small-amplitude fluctuations in a hot mirror plasma. The fast switching of the antennas is controlled using PIN diode switches, which offers the significant advantage of reducing the number of high-cost microwave components and digitizers with high bandwidths and large memory that are required to measure the spatiotemporal behavior of the high-frequency fluctuations. The use of two channels rather than one adds the important function of a simultaneous two-point measurement in either the radial direction or the direction of the antenna array to measure the phase profile of the fluctuations along with the normal amplitude profile. The density fluctuations measured using this system clearly showed the high-frequency coherent fluctuations that are associated with Alfvén-ion-cyclotron (AIC) waves in GAMMA 10. A correlation analysis applied to simultaneously measured density fluctuations showed that the phase component that was included in a reflected microwave provided both high coherence and a clear phase difference for the AIC waves, while the amplitude component showed neither significant coherence nor clear phase difference. The axial phase differences of the AIC waves measured inside the hot plasma confirmed the formation of a standing wave structure. The axial variation of the radial profiles was evaluated and a clear difference was found among the AIC waves for the first time, which would be a key to clarify the unknown boundary conditions of the AIC waves.
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Internal Measurement of Propagation of ICRF Waves by Using Reflectometers on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2015. [DOI: 10.13182/fst14-898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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21
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ICRF Experiment with Phase-Controlled Antennas on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Evaluation of the Axisymmetricity of the Central-Cell Plasma Using a Segmented Limiter on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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23
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ICRF Heating Experiments in Both East and West Anchor Cells on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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Axial Transport of High-Energy Ions due to ICRF Heating on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Two-Point Measurement of High-Frequency Density Fluctuations by Reflectometry in GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Investigation of the Plasma Heating Effects on the End-Loss Ion Flux of the Tandem Mirror GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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27
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Recent ICRF Heating Experiments for a Divertor Simulation Study on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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ICRF Antenna Loading in the Minimum-B Anchor Configuration on GAMMA 10. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Edge Turbulence/Fluctuation Observation at “High Density Mode” in GAMMA 10 by Fast Camera. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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30
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A new frequency-multiplied interferometer system in the GAMMA 10 tandem mirror. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E310. [PMID: 23126970 DOI: 10.1063/1.4731006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A new interferometer is installed on the west anchor cell of the GAMMA 10 tandem mirror. In GAMMA 10, we have used a heterodyne-type interferometer with a 70-GHz IMPATT oscillator and a 150-MHz oscillator for frequency modulation. The new interferometer consists of a 17.5-GHz phase locked dielectric resonator oscillator and a 37.5-MHz temperature-compensated crystal oscillator, as well as frequency multipliers. The main motivation for the new interferometer using frequency multipliers is to achieve a stable and cost effective interferometer. Direct anchor heating experiments with new anchor ion cyclotron range of frequency antennas in both the west and the east anchor cells are carried out. Density increases in both anchor cells are clearly observed using the new interferometer.
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Tangential soft-x ray imaging for three-dimensional structural studies in a reversed field pinch. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:073502. [PMID: 20687717 DOI: 10.1063/1.3455216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Tangential soft-x ray (SXR) imaging diagnostic has been developed and three-dimensional (3D) structure of the internal magnetic surface has been deduced by comparing the experimental and calculated two-dimensional SXR images in a reversed field pinch. The SXR imaging system, consisting of a MCP, a fluorescent plate, and an intensified charge coupled device camera, has been installed in REversed field pinch of Low-Aspect-ratio eXperiment (RELAX) machine. Major characteristics of an experimental SXR image could be reproduced by numerical calculations of the image using a single island model, suggesting a helical hot core in RELAX. The SXR imaging system could be useful for 3D structural studies when tangential and vertical simultaneous imaging systems would be installed, with appropriate numerical modeling of 3D structure of the magnetic surfaces.
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Research Plans for Low-Aspect Ratio Reversed Field Pinch. FUSION SCIENCE AND TECHNOLOGY 2007. [DOI: 10.13182/fst07-a1349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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