Fast Wave Heating and Current Drive in ELMing H-mode Plasmas in DIII-D. PDF Download
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Author:
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Languages : en
Pages : 5
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Book Description
The DIII-D Fast Wave Current Drive (FWCD) program has concentrated on studying the basic physics of direct electron heating and current drive in low density L-mode discharges from its inception in 1991 through 1996. The more recent DIII-D FWCD work has been aimed at extension of the operating regimes of the experiments, including higher total power by combining FW with NB and 110 GHz ECH. Generally, these higher power levels result in H-mode confinement, and in a quasi-steady-state condition, Edge Localized Modes (ELMs). Over the past two years, the DIII-D FWCD systems have been modified to improve their capabilities under a wide range of dynamic antenna loading conditions, such as those characteristic of ELMing H-modes. In this paper, the first results of extending the FWCD studies to ELMing H-mode discharges are presented.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Book Description
The DIII-D Fast Wave Current Drive (FWCD) program has concentrated on studying the basic physics of direct electron heating and current drive in low density L-mode discharges from its inception in 1991 through 1996. The more recent DIII-D FWCD work has been aimed at extension of the operating regimes of the experiments, including higher total power by combining FW with NB and 110 GHz ECH. Generally, these higher power levels result in H-mode confinement, and in a quasi-steady-state condition, Edge Localized Modes (ELMs). Over the past two years, the DIII-D FWCD systems have been modified to improve their capabilities under a wide range of dynamic antenna loading conditions, such as those characteristic of ELMing H-modes. In this paper, the first results of extending the FWCD studies to ELMing H-mode discharges are presented.
Author: Victor L. Granatstein
Publisher: CRC Press
ISBN: 9782881240577
Category : Science
Languages : en
Pages : 524
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Author:
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Category :
Languages : en
Pages : 12
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The noninductive current driven by fast Alfven waves (FWCD) has been applied to discharges in DIII-D with negative central shear. Driven currents as high as 275 kA have been achieved with up to 3 MW of fast wave power with the efficiency and profile as predicted by theory-based modeling. When counter-current FWCD was applied to discharges with negative central shear, the negative shear was strengthened and prolonged, showing that FWCD can help to control the current profile in advanced tokamak discharges. Under some conditions in negative central shear, the plasma spontaneously makes a transition into a regime of improved performance, with a reduction in both the ion and the electron heat diffusivities. Up to 3 MW of fast wave power has been successfully coupled into H-mode discharges with large edge localized modes through use of an innovative decoupler/hybrid power splitter combination.
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Category : Aeronautics
Languages : en
Pages : 692
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Author:
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Category :
Languages : en
Pages : 13
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The physics of non-inductive current drive and current profile control using the fast magnetosonic wave has been demonstrated on the DIII-D tokamak. In non-sawtoothing discharges formed by neutral beam injection (NBI), the radial profile of the fast wave current drive (FWCD) was determined by the response of the loop voltage profile to co, counter, and symmetric antenna phasings, and was found to be in good agreement with theoretical models. The application of counter FWCD increased the magnetic shear reversal of the plasma and delayed the onset of sawteeth, compared to co FWCD. The partial absorption of fast waves by energetic beam ions at high harmonics of the ion cyclotron frequency was also evident from a build up of fast particle pressure near the magnetic axis and a correlated increase in the neutron rate. The anomalous fast particle pressure and neutron rate increased with increasing NBI power and peaked when a harmonic of the deuterium cyclotron frequency passed through the center of the plasma. The experimental FWCD efficiency was highest at 2 T where the interaction between the fast waves and the beam ions was weakest; as the magnetic field strength was lowered, the FWCD efficiency decreased to approximately half of the maximum theoretical value.
Author:
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Category :
Languages : en
Pages : 9
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Book Description
Fast wave current drive and electron cyclotron current drive experiments have been performed on the DIII-D tokamak as part of the advanced tokamak program. The goal of this program is to develop techniques for controlling the profile of the current density in order to access regimes of improved confinement and stability. The experiments on fast wave current drive used a four strap antenna with 900 phasing between straps. A decoupler was used to help maintain the phasing, and feedback control of the plasma position was used to keep the resistive loading constant. RF pickup loops demonstrate that the directivity of the antenna is as expected. Plasma currents up to 0.18 MA were driven by 1.5 MW of fast wave power. Electron cyclotron current drive experiments at 60 GHz have shown 0.1 MA of plasma current driven by 1 MW of power. New fast wave and electron cyclotron heating systems are in development for DIII-D, so that the goals of the advanced tokamak program can be carried out.
Author: Ronald Prater
Publisher: American Institute of Physics
ISBN: 9781563965364
Category : Science
Languages : en
Pages : 528
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Book Description
Proceedings of the conference sponsored by General Atomics and the American Physical Society, and held in May 1995 to address use of radio frequency fields for plasma heating, current drive, and MHD control in plasmas. Contributions were also accepted in the technical areas of wave launching, rf sou
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 332
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Book Description
Author: C. Varandas
Publisher: Elsevier
ISBN: 0444599754
Category : Science
Languages : en
Pages : 1057
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Book Description
The objective of these proceedings was to provide a platform for the exchange of information on the design, construction and operation of fusion experiments. The technology which is being developed for the next step devices and fusion reactors was also covered.
Author: Donald B. Batchelor
Publisher: American Institute of Physics
ISBN:
Category : Science
Languages : en
Pages : 424
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Book Description
The proceedings of the Ninth Topical Conference on [title], held in Charleston, SC, August 1991, comprise invited and contributed papers on topics in the areas of electron cyclotron range of frequencies, lower hybrid range of frequencies, ion cyclotron range of frequencies, current drive, RF technol
