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High beta studies on ISX-B with neutral beam injection

Description: Injection of H/sup 0/ into D/sup +/ plasmas with beam power P/sub b/ of up to 1.7 MW has produced rms betas of approx. 4%, volume-averaged betas of approx. 3%, and central betas of approx. 10% in the ISX-B tokamak. Although theoretical calculations indicate that the observed equilibria may be unstable to ballooning modes, no catastrophic loss of confinement has been observed, and beta continues to increase with injection power. In these beam-dominated high-beta discharges the electron and ion e… more
Date: September 1980
Creator: Sheffield, J.; Bates, S.C. & Bush, C.E.
Partner: UNT Libraries Government Documents Department
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Impurity studies in fusion devices using laser-fluorescence-spectroscopy

Description: Resonance fluorescence excitation of neutral atoms using tunable radiation from dye lasers offers a number of unique advantages for impurity studies in fusion devices. Using this technique, it is possible to perform local, time-resolved measurements of the densities and velocity distributions of metallic impurities in fusion devices without disturbing the plasma. Velocities are measured by monitoring the fluorescence intensity while tuning narrow bandwidth laser radiation through the Doppler - … more
Date: August 1, 1980
Creator: Husinsky, W.R.
Partner: UNT Libraries Government Documents Department
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Gettering in ISX-B

Description: Gettering is used in the ISX-B tokamak to reduce the impurity concentration. This paper documents the gettering process used, and compares the expected changes in recycling and radiation with those observed experimentally. The enlargement of the operating regime (1/q, anti n/sub e/ R/B/sub phi/ space) is discussed. Finally, the effect on one of the objectives of the experimental program, that of obtaining high values of beta, is described.
Date: January 1, 1982
Creator: Wootton, A.J.; Edmonds, P.H.; Isler, R.C. & Mioduszewski, P.
Partner: UNT Libraries Government Documents Department
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Plasma position dynamics of ISX tokamak

Description: Perturbation equations of a tokamak plasma equilibrium position have been developed. Neglecting second and higher order effects, oscillatory high frequency solution is obtained, and an approximated low frequency plasma motion dynamics transfer function is derived. This function allows a manageable study of a tokamak plasma equilibrium position stability and practical syntheses of the associated plasma position feedback control systems. One of the major parameters governing plasma equilibrium po… more
Date: January 1, 1977
Creator: Burenko, O.
Partner: UNT Libraries Government Documents Department
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Neutral injection experiments on the ISX-B tokamak

Description: The following topics are described: (1) review of confinement scaling in ISX-B with strong neutral injection in clean plasmas, (2) discussion of observed energy confinement improvement in slightly contaminated discharges (factor less than or equal to 2), and (3) preliminary evaluation of confinement with balanced neutral beam injection. (MOW)
Date: January 1, 1983
Creator: Scott, S.D.
Partner: UNT Libraries Government Documents Department
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Assembly of ISX

Description: The Impurity Study Experiment, a moderate size tokamak, was recently assembled at ORNL. Demountable toroidal field coils allowed for the assembly of major components at remote locations and rapid installation into ISX. A discharge cleaning plasma was generated in ISX six weeks after the arrival of the final toroidal field coil. A chronological summary of the assembly is presented, emphasizing features designed to aid in assembly and maintenance. A cross-section of the machine showing the major … more
Date: January 1, 1977
Creator: Durfee, N. W.
Partner: UNT Libraries Government Documents Department
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Magnetic field computations for ISX using GFUN-3D

Description: This paper presents a comparison between measured magnetic fields and the magnetic fields calculated by the three-dimensional computer program GFUN-3D for the Impurity Study Experiment (ISX). Several iron models are considered ranging in sophistication from 50 to 222 tetrahedra iron elements. The effects of air gaps and the efforts made to simulate effects of grain orientation and packing factor are detailed. The results obtained are compared with the measured magnetic fields, and explanations … more
Date: January 1, 1977
Creator: Cain, W.D.
Partner: UNT Libraries Government Documents Department
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ISX-B impurity study program

Description: A review of some of the problems associated with tokamak impurities is given. The ISX research program is described. (MOW)
Date: January 1, 1979
Creator: Langley, R. A.
Partner: UNT Libraries Government Documents Department
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Upgrade of MHD data acquisition system from ISX-B (Impurity Study Experiment) to ATF (Advanced Toroidal Facility)

Description: The data acquisition system assembled to study magnetohydrodynamic (MHD) activity on the Impurity Study Experiment (ISX-B) tokamak at Oak Ridge National Laboratory (ORNL) is being revised for use on the Advanced Toroidal Facility (ATF). The new hardware and software architectures are based on ISX-B experience and will feature different modes of operation for storing various subsets of available data, a user interface that requires less routine activity than the earlier system, and continued sup… more
Date: January 1, 1987
Creator: Bell, J. D. & Pare, V. L.
Partner: UNT Libraries Government Documents Department
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Design of the ISX-B differentially pumped bellows

Description: The structural design and operational aspects of the ISX-B differentially pumped bellows assembly are discussed. The ISX-B vacuum vessel consists of two monolithic halves which are rectangular in cross section and joined together by short bellows which provide electrical resistance around the vesel in the toroidal direction. The bellows are unable to withstand atmospheric pressure and must be mounted within an outer, thick-wall vessel with the space between bellows and wall being pumped down to… more
Date: January 1, 1977
Creator: Goranson, P.L.
Partner: UNT Libraries Government Documents Department
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Performance characterization of pneumatic single pellet injection system

Description: The Oak Ridge National Laboratory single-shot pellet injector, which has been used in plasma fueling experiments on ISX and PDX, has been upgraded and extensively instrumented in order to study the gas dynamics of pneumatic pellet injection. An improved pellet transport line was developed which utilizes a 0.3-cm-diam by 100-cm-long guide tube. Pellet gun performance was characterized by measurements of breech and muzzle dynamic pressures and by pellet velocity and mass determinations. Velocitie… more
Date: January 1, 1982
Creator: Schuresko, D. D.; Milora, S. L.; Hogan, J. T.; Foster, C. A. & Combs, S. K.
Partner: UNT Libraries Government Documents Department
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ISX objectives and physics

Description: The ISX-B program has achieved average beta values of 1.8% in a relatively clean plasma with neutral beam injection power greater than 10 times ohmic power input. Total beta has increased smoothly with beam power so far and exceeded theoretical limits with no indication that ballooning or any other instability is significantly increasing the energy loss rate.
Date: January 1, 1979
Creator: Mihalczo, J.T.
Partner: UNT Libraries Government Documents Department
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Initial testing of coated limiters in ISX-B

Description: Low-Z coatings on graphite substrates have been developed for testing as limiters in the Impurity Study Experiment (ISX-B) tokamak. Laboratory and tokamak testings have been accomplished. The laboratory tests included thermal shock experiments by means of pulsed e-beam irradiation, arcing experiments, and hydrogen and xenon ion erosion experiments. The tokamak testing consisted of ohmically heated plasma exposures with energy depositions up to 10 kJ/discharge on the limiters. The coatings, appl… more
Date: January 1, 1980
Creator: Langley, R. A.; Emerson, L. C.; Whitley, J. B. & Mullendore, A. W.
Partner: UNT Libraries Government Documents Department
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Objectives of the tokamak magnetic fusion program

Description: A brief description of the tokamak program as related to the national magnetic confinement program is given. Primary areas where the ISX and PDX tokamaks are contributing to the program are discussed. (MOW)
Date: January 1, 1979
Creator: Jernigan, T.C.
Partner: UNT Libraries Government Documents Department
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Determination of the global recombination rate coefficient for the ISX-B Tokamak

Description: The global recombination rate coefficient for hydrogen has been measured for the ISX-B tokamak vacuum vessel for various surface conditions. The measurements were performed by observing the rate of decrease of gas pressure in the vessel during a glow discharge. The parameters of the glow discharge and the complete experimental method are described. Previously published analytic and numerical models are used for data analysis. The effects of surface contamination on the results are described. Fo… more
Date: January 1, 1983
Creator: Langley, R. A. & Howe, H. C.
Partner: UNT Libraries Government Documents Department
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High beta results in ISX-B with intense neutral beam injection

Description: Experiments on the ISX-B device show a deterioration in confinement at high beam power. In particular the electron energy confinement time falls catastrophically with increasing beam power. The maximum volume averaged beta values achieved are <2.5%; this is much less than would be predicted by extrapolating the low power data. Elongation has not been observed to have any significant effect on the maximum attainable beta, perhaps due to the limited range of both internal and external elongation.… more
Date: January 1, 1982
Creator: Edmonds, P. H.; Bates, S. C. & Bell, J. D.
Partner: UNT Libraries Government Documents Department
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Results of pellet injection into ISX-B

Description: Improvements in plasma performance with pellet injection have been achieved in several tokamaks in recent experiments. On the Impurity Study Experiment (ISX-B), an increase in plasma energy by as much as 50%, has been observed following pellet injection. With 1.5-mm pellets, the value for tau/sub E/, the gross energy confinement time determined from ..beta../sub equil/, has peaked at 1.7 times ISX-B scaling for n/sub e/ = 6 x 10/sup 13/ cm/sup -3/ in both well-gettered and ungettered discharges… more
Date: January 1, 1985
Creator: Schuresko, D.D.
Partner: UNT Libraries Government Documents Department
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Impurity behavior in the ISX-B tokamak

Description: Any discussion of impurity behavior during neutral-beam injection in ISX-B is best formulated in terms of the distinctive differences observed between ohmically heated, co-injection, and counter-injection discharges. In ohmically heated discharges both the production and the transport of impurities depend upon whether the working gas is hydrogen or deuterium. The influx of oxygen is almost the same for both cases, but the influx of metals is about a factor of 3 larger in the deuterium discharge… more
Date: January 1, 1982
Creator: Isler, R.C.; Murray, L.E. & Edmonds, P.H.
Partner: UNT Libraries Government Documents Department
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ORNL fusion programs in industry

Description: A brief review of ORNL's research program on the large coil project, EBT, ISX, and the FED is given. Their subcontracting practices are also mentioned. (MOW)
Date: January 1, 1980
Creator: Rosenthal, M.W.
Partner: UNT Libraries Government Documents Department
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MHD Fluctuations in ISX-B

Description: Studies of beam-heated plasmas with Mirnov coils have been continued. Previous observations have shown no correlation between the (1;1) driven modes and confinement; however at higher frequencies, such a correlation can be found. A band-pass filter, monitoring frequencies approx. = 150 kHz, and the integrated fluctuation amplitude from the high-frequency wave-form data are used to obtain B/sub theta//B/sub theta/. The results show increasing B/sub theta//B/sub theta/ is associated with decreasi… more
Date: January 1, 1984
Creator: Bell, J. D.; Dunlap, J. L.; Pare, V. K. & Wootton, A. J.
Partner: UNT Libraries Government Documents Department
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Survey of Modes and Their Effects in ORMAK, ISX-A, and ISX-B

Description: A comparison of some features of the three tokamaks is given. The ORMAK and ISX-A have ceased operation. The ISX-B has completed a checkout phase with studies of circular, ohmically heated plasmas in which it performed much like ISX-A. Shaped and injection heated plasmas are being studied. Diagnostics for mode structures were the usual Mirnov loops for approx.B/sub theta/ and collimated soft x-ray detectors for the internal fluctuations approx.X. The approx.X measurements on ISX-A, and thus far… more
Date: February 14, 1979
Creator: Dunlap, J. L.; Burris, R. D.; Harris, J. H.; Navarro, A. P. & Pare, V. K.
Partner: UNT Libraries Government Documents Department
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Time dependence of gases from plasma-wall interactions in ISX-A

Description: Numerous papers have been published concerning radiation damage and thermal properties of first walls in tokamak reactors. However vacuum properties are also important, particularly as regards the adsorption and release of gases during and immediately following tokamak discharges. We have studied the time evolution of working and impurity gases by means of a quadrupole mass spectrometer attached to the ISX-A tokamak. These results were compared with measurements in a similar (304L stainless ste… more
Date: January 1, 1979
Creator: Simpkins, J.E. & Colchin, R.J.
Partner: UNT Libraries Government Documents Department
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Minority hydrogen isotope recycling in ISX-B

Description: A short burst of H/sub 2/ was puffed into an established ohmically-heated D/sub 2/ plasma at 80 ms into the discharge. H/D ratios were determined throughout the discharge from relative H/sub ..beta../D/sub ..beta../ spectral intensities using a high resolution spectrometer equipped with an oscillating mirror for repetitively scanning a 10 A region around 4861 A. The spectrometer viewed the plasma along a major radius approx. 90/sup 0/ toroidally from the limiter and approx. 180/sup 0/ toroidall… more
Date: January 1, 1981
Creator: Roberto, J.B.; Howe, H.C.; Isler, R.C. & Murray, L.E.
Partner: UNT Libraries Government Documents Department
open access

Electron cyclotron heating experiment on the ISX-B tokamak

Description: This paper describes apparatus that will be used to provide 200 kW of microwave heating at 28 GHz to the ISX-B tokamak. The program goals and a brief explanation of the principles of microwave heating in a plasma are included in the introduction, and the current status of the project is outlined in the conclusion.
Date: January 1, 1979
Creator: Campen, G.L.; England, A.C.; Loring, C.M. & Wright, W.L.
Partner: UNT Libraries Government Documents Department
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