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Initial Operation of the NSTX Phased Array for Launching High Harmonic Fast Waves

Description: A high harmonic fast wave (HHFW) antenna array, designed to provide up to 6 MW of power at 30 MHz for heating and current drive applications, has been operated on the NSTX experiment at Princeton Plasma Physics Laboratory (PPPL). The full array consists of twelve evenly spaced, identical current strap modules connected in pairs. Each pair is connected as a half-wave resonant loop and is intended to be driven by one transmitter, allowing rapid phase shift between transmitters. A decoupling netwo… more
Date: February 22, 2001
Creator: Ryan, P.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fast Soft X-ray Images of MHD Phenomena in NSTX

Description: A variety of MHD phenomena have been observed on NSTX. Many of these affect fast particle losses, which are of major concern for future burning plasma experiments. Usual diagnostics for studying these phenomena are arrays of Mirnov coils for magnetic oscillations and PIN diode arrays for soft x-ray emission from the plasma core. Data reported here are from an unique fast soft x-ray imaging camera (FSXIC) with a wide-angle (pinhole) tangential view of the entire plasma minor cross section. The c… more
Date: July 21, 2008
Creator: C.E. Bush, B.C. Stratton, J. Robinson, L.E. Zakharov, E. D. Fredrickson, D. Stutman, K. Tritz
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stability Properties of Toroidal Alfven Modes Driven by Fast Particles

Description: In this report, the issues of Alfven mode stability in advanced tokamak regimes are addressed based on recent developments in theory, computational methods, and progress in experiments. The instability of Toroidal Alfven Eigenmodes (TAE) is analyzed for spherical tokamaks, such as the National Spherical Torus Experiment NSTX at the Princeton Plasma Physics Laboratory using the NOVA-K code. Chirping modes in the Alfven frequency range observed in JT-60U during the NNBI heating at energies eb0= 3… more
Date: November 1, 1999
Creator: Cheng, C. Z.; Hill, K.; Gorelenkov, N. N.; Bernabei, S. & al, et
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Kinetic Profiles in NSTX Plasmas

Description: The National Spherical Torus Experiment (NSTX) is a low aspect ratio (R/a approximately 1.3) device with auxiliary heating from neutral-beam injection (NBI) and high-harmonic fast-wave heating (HHFW). Typical NSTX parameters are R(subscript ''0'') = 85 cm, a = 67 cm, I(subscript ''p'') = 0.7-1.4 MA, B(subscript ''phi'') = 0.25-0.45 T. Three co-directed deuterium neutral-beam sources have injected P(subscript ''NB'') less than or equal to 4.7 MW. HHFW plasmas typically have delivered P(subscript… more
Date: July 10, 2001
Creator: Bell, R. E.; LeBlanc, B. P.; Bourdelle, C.; Ernst, D. R.; Fredrickson, E. D.; Gates, D. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An Edge Rotation and Temperature Diagnostic on NSTX

Description: A new diagnostic for the National Spherical Torus Experiment (NSTX) is described whose function is to measure ion rotation and temperature at the plasma edge. The diagnostic is sensitive to C III, C IV, and He II intrinsic emission, covering a radial region of 15 cm at the extreme edge of the outboard midplane. Thirteen chords are distributed between toroidal and poloidal views, allowing the toroidal and poloidal rotation and temperature of the plasma edge to be simultaneously measured with 10 … more
Date: August 29, 2003
Creator: Biewer, T. M.; Bell, R. E.; Feder, R.; Johnson, D. W. & Palladino, R. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Results of High Harmonic Fast Wave Heating Experiments on NSTX

Description: The study of high-harmonic fast-wave (HHFW) heating and current drive is being conducted on the National Spherical Torus Experiment (NSTX) device to determine the physics of applying radio-frequency (rf) waves at high harmonics (approximately 10-20) of the ion cyclotron frequency in this high-beta plasma regime and to extend the performance of the NSTX plasma. The magnetic field of this low aspect ratio device is lower (less than or equal to 0.35 T for this work) than that for the typical moder… more
Date: August 9, 2001
Creator: Hosea, J. C.; Bell, R. E.; Bitter, M.; Bonoli, P.; Carter, M.; Gates, D. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of Toroidal Rotation Sshear on Toroidicity-induced Alfven Eigenmodes in the National Spherical Torus Experiment

Description: The effects of a sheared toroidal rotation on the dynamics of bursting Toroidicity-induced Alfven eigenmodes are investigated in neutral beam heated plasmas on the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40 557 (2000)]. The modes have a global character, extending over most of the minor radius. A toroidal rotation shear layer is measured at the location of maximum drive for the modes. Contrary to results from other devices, no clear evidence of increased damping … more
Date: August 19, 2010
Creator: Podesta, M.; Fredrickson, E. D.; Gorelenkov, N. N.; LeBlanc, B. P.; Heidbrink, W. W.; Crocker, N. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

HIGH PERFORMANCE PLASMAS ON THE NATIONAL SPHERICAL TORUS EXPERIMENT

Description: The National Spherical Torus Experiment has produced toroidal plasmas at low aspect ratio (A = R/a = 0.86d0.68m - 1.3, where R is the major radius and a is the minor radius of the torus) with plasma currents of 1.4MA. The rapid development of the machine has led to very exciting physics results during the first full year of physics operation. Pulse lengths in excess of 0.5s have been obtained with inductive current drive. Up to 4MW of High Harmonic Fast Wave (HHFW) heating power has been applie… more
Date: January 1, 2001
Creator: Gates, D. & Peng, Yueng Kay Martin
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
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Initial Studies of Core and Edge Transport of NSTX Plasmas

Description: Rapidly developing diagnostic, operational, and analysis capability is enabling the first detailed local physics studies to begin in high-beta plasmas of the National Spherical Torus Experiment (NSTX). These studies are motivated in part by energy confinement times in neutral-beam-heated discharges that are favorable with respect to predictions from the ITER-89P scaling expression. Analysis of heat fluxes based on profile measurements with neutral-beam injection (NBI) suggest that the ion therm… more
Date: September 19, 2001
Creator: Synakowski, E. J.; Bell, M. G.; Bell, R. E.; Bush, C. E.; Bourdelle, C.; Darrow, D. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Multispecies Density and Temperature Gradient Dependence of Quasilinear Particle and Energy Fluxes

Description: The variations of the normalized quasilinear particle and energy fluxes with artificial changes in the density and temperature gradients, as well as the variations of the linear growth rates and real frequencies, for ion temperature gradient and trapped-electron modes, are calculated. The quasilinear fluxes are normalized to the total energy flux, summed over all species. Here, realistic cases for tokamaks and spherical torii are considered which have two impurity species. For situations where … more
Date: August 9, 2004
Creator: Rewoldt, G.; Budny, R.V. & Tang, W.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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