1,529 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Thermonuclear Devices"  
Results: 1 - 24 next
open access

The multipulse Thomson scattering diagnostic on the DIII-D tokamak

Description: This paper describes the design and operation of a 40-spatial channel Thomson scattering system that uses multiple 20 Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. Interference filter polychromators disperse the scattered light which is detected by silicon avalanche photodiodes. The measurable temperature range from 10 eV to 20 keV and the minimum detectable density is about 2 {times} 10{sup 18} m{sup {minus}3}. Las… more
Date: September 1, 1991
Creator: Carlstrom, T. N.; Campbell, G. L.; DeBoo, J. C.; Evanko, R. G.; Evans, J.; Greenfield, C. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Stress analysis of MFTF-B getter system bellows. Final report

Description: The MFTF-B design includes a retractable getter system. Eight getter assemblies are planned (4 in each end plug). Electrically heated Ti wires are mounted on a telescoping insertion mechanism and, between machine shots (pulses), are extended into the chamber in the vicinity of inward-facing water-cooled magnet liners. During the shots, the sublimators must be withdrawn because they will intrude into plasma and diagnostic space. Each of the getter assemblies will be mounted on the exterior of th… more
Date: April 1, 1982
Creator: Tokarz, F. J.; Johnson, J. J.; Mukherjee, A. N. & Dalder, E. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Non-linear instability of DIII-D to error fields

Description: Otherwise stable DIII-D discharges can become nonlinearly unstable to locked modes and disrupt when subjected to resonant m = 2, n = 1 error field caused by irregular poloidal field coils, i.e. intrinsic field errors. Instability is observed in DIII-D when the magnitude of the radial component of the m = 2, n = 1 error field with respect to the toroidal field is B{sub r21}/B{sub T} of about 1.7 {times} 10{sup {minus}4}. The locked modes triggered by an external error field are aligned with the … more
Date: October 1, 1991
Creator: La Haye, R. J. & Scoville, J. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Potential for use of high-temperature superconductors in fusion reactors

Description: The present rate of development of high-temperature superconductors (HTSs) is sufficiently rapid that there may be opportunities for their use in contemporary fusion devices such as the International Thermonuclear Experimental Reactor (ITER). The most likely 1application is for delivering power to the superconducting magnets, especially in substituting for the current leads between the temperatures of 4 K and 77K. A second possible application of HTSs is as a liquid-nitrogen-cooled power bus, c… more
Date: January 1, 1991
Creator: Hull, J.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fueling of tandem mirror reactors

Description: This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed fo… more
Date: January 1, 1985
Creator: Gorker, G. E. & Logan, B. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

TCT hybrid preconceptual blanket design studies

Description: The conceptual design of a tokamak fusion-fission (hybrid) reactor, which produces electric power and fissile material, has been performed in a cooperative effort between Princeton's Plasma Physics Laboratory (PPPL) and Battelle's Pacific Northwest Laboratories (PNL). PPPL, who had overall project lead responsibility, designed the fusion driver system. Its core consists of a tokamak plasma maintained in the two-component torus (TCT) mode by both D and T beams and having a single null poloidal d… more
Date: January 1, 1978
Creator: Aase, D. T.; Bampton, M. C. C.; Doherty, T. J.; Leonard, B. R.; McCann, R. A.; Newman, D. F. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The interpretation of reflectometry measurements of plasma fluctuations

Description: Wave reflections from density fluctuations with magnitudes and frequencies typical of drift waves have been investigated. Both drift waves and the reflected phase and amplitude depend on the density gradient scale length, and this common feature implies that both the angular deviation of a normally propagating wave and the phase change on reflection are of order unity. Thus the surface will always appear rough'' and amplitude variations will always be large. For smaller amplitude waves numerica… more
Date: October 1, 1991
Creator: Bretz, N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Recent progress on ATF

Description: The ATF experiment will test improvements to high-beta, steady-state toroidal confinement using external helical fields. The device design has been optimized to (1) provide direct access to the high-beta second-stability regime, (2) have sufficient flexibility to study a large range of toroidal configurations both with and without plasma current, (3) test the reduction of low-collisionality transport by EXB drifts induced by the self-consistent radial electric field, and (4) permit steady-state… more
Date: January 1, 1984
Creator: Neilson, G.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Classification of disruptions in PBX

Description: Disruptions in beam-heated plasmas on PBX were studied by classifying precursor oscillations detected by a soft x-ray imaging system and Mirnov coils. A data base consisting of 80 discharges was constructed. In low I/sub p/ operation, attainable ..beta../sub T/ values are limited by disruptions preceded by m = 1 activity at the center and coupled an m/n = even/1 mode. In high I/sub p/ and high ..beta../sub T/ operation with high indentation, the sawtooth activity disappears. At these disruption… more
Date: September 1, 1985
Creator: Itami, K.; Jahns, G.; Yamada, H. & McGuire, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ORMAK upgrade ohmic coil generator protection

Description: This report describes methods which can be used to limit the voltage across the generator for normal operation and various ground faults. It also contains quantitative information, obtained from the computer study, which can be used for evaluating the protection methods cost-wise.
Date: January 1, 1978
Creator: Campen, G. L.; Easter, R. B. & Nickels, L. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Application of optical fluctuation diagnostics to transport studies in high temperature tokamak plasmas

Description: First data was obtained from the TFTR BES system in May 1990, after the prototype 4-channel system with photomultiplier detectors from PBX-M was transferred to the TFTR Hot Cell. The system was expanded to 16 spatial channels during the Summer 1990 run period, and data of interest was obtained near the end of the run in October 1990. The most attention has been given to a radial profile data set obtained for an L-mode plasma condition in TFTR, where we characterized the nature of the long-wavel… more
Date: January 1, 1991
Creator: Fonck, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Hot-ion distribution function in ORMAK, the Oak Ridge Tokamak

Description: A distortion of the Maxwellian ion-energy distribution function in tokamak-produced plasmas may be revealed in the spectral-line radiation. We report experimental evidence that (1) a change in the value of Z/sub eff/, (2) delayed gas injection, (3) neutral beam injection, and (4) liner cleaning procedures can alter the profile of the Balmer-..cap alpha.. (6563 A) line of hydrogen. The distortion is analyzed in terms of an effective toroidal-drift velocity, ion-temperature relation.
Date: March 1, 1978
Creator: Neidigh, R.V. & Sigmar, D.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neoclassical transport in stellarators

Description: The stellarator neoclassical transport due to particles trapped in local helical wells is calculated in the low-collisionality regime using a systematic expansion. The behavior of electron transport is found to be the same over a wide range of energies, but the behavior of ion transport for low energy ions is found to be different than that for high energy ions. Furthermore, the electron fluxes do not vary with the change in the radial ambipolar electric field nearly as much as do the ion fluxe… more
Date: September 1, 1985
Creator: Ho, D.D.M. & Kulsrud, R.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Shear alfven resonances in Tokapole II

Description: It has been suggested that efficient heating can occur by coupling energy through the shear Alfven resonance that is predicted to occur at particular locations within inhomogeneous plasmas. This heating mechanism should be applicable to tokamaks; however, the existence of the resonances in tokamaks has not yet been established experimentally. We present here direct observations of localized enhancement in the driven wave magnetic field which are compatible with theoretical predictions for the s… more
Date: March 1, 1982
Creator: Witherspoon, F.D.; Prager, S.C. & Sprott, J.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Study of impurities in the Tandem Mirror Experiment using extreme-ultraviolet spectroscopy

Description: Impurities in the Tandem Mirror Experiment (TMX) have been studied using extreme ultraviolet spectroscopy. Three time-resolving absolutely-calibrated normal-incidence monochromators, one on each section of TMX, were used to study the impurity emissions in the wavelength range of 300 A to 1600 A. The instruments on the east end cell and central cell were each capable of obtaining spatially-resolved profiles from 22 chords of the plasma simultaneously while the instrument on the west end cell mon… more
Date: May 12, 1982
Creator: Strand, O. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Radially resolved measurements of ''q'' on the ATC tokamak

Description: This paper describes a new technique for directly measuring the safety factor, or q, profile in a tokamak. A tightly collimated neutral beam capable of injecting approximately 100 mA of 30 keV deuterium atoms was mounted on the ATC tokamak. By proper tangential aiming of the beam a strong concentration of circulating fast ions was created at a chosen plasma minor radius. By examining the orbits of these ions with a multi-sight-line charge exchange detector, it was possible to measure the shifts… more
Date: April 1, 1978
Creator: Goldston, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DAS performance analysis

Description: This report begins with an overview of the Data Acquisition System (DAS), which supports several of PPPL's experimental devices. Performance measurements which were taken on DAS and the tools used to make them are then described.
Date: February 1, 1984
Creator: Bates, G.; Bodine, S.; Carroll, T. & Keller, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A cryogenic system design for the international thermonuclear experimental reactor (ITER)

Description: A conceptual design for ITER was completed last year. The author developed a suitable cryogenic system for ITER as part of this conceptual design effort. An overview of the design is reported. Emphasis is on the fact that cryogenics is a mature science, and a system supporting ITER needs can be made from time-proven components without loss of efficiency or reliability. Because of the large size of the ITER cryogenic system, large numbers of compressors and expanders must be used. Very high reli… more
Date: September 25, 1991
Creator: Slack, D.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of weldments in Type 21-6-9 stainless steel for Compact Ignition Tokamak structural applications: Phase 1

Description: Primary design considerations for the Compact Ignition Tokamak toroidal field-coil cases are yield strength and toughness in the temperature range from 77 to 300 K. Type 21-6-9 stainless steel, also still known by its original Armco Steel Company trade name Nitronic 40, is the proposed alloy for this application. It has high yield strength and usually adequate base metal toughness, but weldments in thick sections have not been adequately characterized in terms of mechanical properties or hot-cr… more
Date: June 1, 1991
Creator: Alexander, D. J.; Goodwin, G. M. & Bloom, E. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Transport, stability and relaxation of a spheromak

Description: We consider a zero-..beta.. spheromak contained in a rectangular region having perfectly conducting boundaries in its minimum energy state, and we calculate its evolution. Our results may be summarized as follows. Since this state is a stable equilibrium, the initial evolution of the plasma is caused by diffusion. We simulate this using a transport code. We find that q at the magnetic axis drops and q(r) becomes flat. When q on axis drops below 0.5, the spheromak becomes unstable to an n = 2 ki… more
Date: January 1, 1984
Creator: Sgro, A. G.; Marklin, G. & Mirin, A. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of high aspect ratio on ITER maintenance design

Description: The International Thermonuclear Experimental Reactor (ITER) baseline machine configuration and auxiliary systems design specify maintainability and repairability as fundamental requirements. Two important maintenance requirements for ITER are a device that is fully remotely maintainable, with the provision for hands-on maintenance wherever possible, and the ability to maintain components with short lives or high failure rates without moving other components or disturbing the machine's internal … more
Date: January 1, 1991
Creator: Herrick, T.J.; Davis, F.C.; Hollis, M.J. & Lousteau, D.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen