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Negative ion-based neutral injection on DIII-D

Description: High energy negative ion-based neutral beam injection is a strong candidate for heating and non-inductive current drive in tokamaks. Many of the questions related to the physics and engineering of this technique remain unanswered. In this paper, we consider the possibility of negative ion-based neutral beam injection on DIII-D. We establish the desired parameter space by examining physics trades. This is combined with potential design constraints and a survey of component technology options to … more
Date: January 1, 1990
Creator: Stewart, L. D.; Bhadra, D. K.; Colleraine, A. P. & Kim, J.
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Partner: UNT Libraries Government Documents Department
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Radiation Shielding Design Considerations for Doublet III

Description: Calculations and measurements were made of the bremsstrahlung (x-ray) doses resulting from runaway electron shots at Doublet III. The analysis considered direct, wall-scattered, and skyshine contributions. Reasonably good agreement was obtained between calculations and measurements. The x-ray dose in the control room was about 1 mR per runaway shot, while that at the north boundary was undetectable, with a calculated value of 0.05 mR per shot. These low doses attest to the adequacy of the 2 ft … more
Date: June 1, 1980
Creator: Engholm, B. A.
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Partner: UNT Libraries Government Documents Department
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Alfven wave stability in D-III-D

Description: Within the framework of the global Alfven eigenmode theory in a cylindrical background plasma, I examine the excitation of global Alfven eigenmodes by intense neutral beam injection in the D III-D tokamak operating at General Atomics. I have considered two separate sets of experimental conditions, a low power'' set of cases using 10MW of hydrogen beams, and a high power'' shot of 20MW of deuterium beams. My results are particularly sensitive to the background density profile. For parabolic back… more
Date: September 1, 1989
Creator: Campbell, R.B. (Lawrence Livermore National Lab., CA (USA)) & Samec, T.K. (TRW, Inc., Redondo Beach, CA (USA))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Doublet III neutral beam injector test tank cryopanel design

Description: A simple condensing cryopanel has been designed for the Doublet III neutral beam test tank with a 320,000 liters per second pumping capacity for hydrogen. This maintains a vacuum in the test tank which simulates the Doublet III vessel, 1.3 x 10/sup -3/ Pa (approx.10/sup -5/ torr). The hydrogen gas load comes from the beam striking the test tank calorimeter and amounts to about 7.2 torr liters per second. The cryopanel is cylindrical shaped with a liquid helium (LHe) surface that pumps through l… more
Date: March 1, 1980
Creator: Doll, D.W.; Kamperschroer, J.H. & Arend, P.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modification of Doublet III to a large Dee facility

Description: The Doublet III facility represents a unique opportunity to convert an existing device to a powerful test bed for FED design and operation issues. Such a conversion is made possible by virtue of the demountability of the devices toroidal field coils. Doublet III can be partially disassembled then reassembled with a large dee-shaped vacuum vessel and associated poloidal coils and structure. Doublet III presently possesses or is acquiring adequate auxiliary heating (14 MW of neutral beams and 2 M… more
Date: October 1, 1981
Creator: Davis, L. G. & Rawls, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Properties of diverted plasmas with magnetically expanded flux surfaces

Description: Vertical elongated 1.3:1 elliptical plasmas in which the outermost flux surfaces are magnetically expanded and diverted by external coils into the lower half of the Doublet III vacuum vessel are described. Approximately 5 cm of the nominal 45 cm plasma minor radius is diverted to the lower chamber. The diverted flux is expanded by more than a factor of ten before reaching the vessel wall. Photographic measurements show diffused hydrogen recycling light in the lower half of the vessel, with grea… more
Date: July 1, 1980
Creator: Ali Mahdavi, M.; Ohyabu, N. & Baker, D.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy confinement in Doublet III with high-Z limiters

Description: This report describes the experimental measurements and data analysis techniques used to evaluate the energy confinement in noncircular plasmas produced in Doublet III. Major aspects of the confinement measurements and analysis techniques are summarized. Machine parameters, diagnostic systems and discharge parameters relavent to the confinement measurements are given. Magnetic analysis techniques used to determine the plasma shape are reviewed. Scaling of the on-axis values of electron temperat… more
Date: February 1, 1980
Creator: Marcus, F. B.; Adcock, S. J.; Baker, D. R.; Blau, F. P.; Brooks, N. H.; Chase, R. P. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Shaping and characteristics of ohmically heated noncircular plasmas in Doublet III

Description: Ohmically heated dee, droplet and doublet plasmas with vertical elongations of up to 3.2 have been produced in Doublet III. Doublet configurations are now obtained by controlled merging of the two current channels of a droplet discharge. All discharges have low levels of impurities and central radiated power and achieve high density relative to B/sub T//R scaling. The energy confinement follows the standard circular cross-section Alcator scaling law. The lack of significant improvement in the c… more
Date: June 1, 1980
Creator: Wesley, J.C.; Angel, T. & Armentrout, C.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron-cyclotron-heating results on JFT-2, and their implications for the Doublet III ECH design

Description: Electron cyclotron heating experiments are described in which 28 GHz microwave power is injected into the JFT-2 tokamak. Ordinary mode power injected from the low field side increased the central electron temperature from 600 eV to 1000 eV with 110 kW, for densities below the ordinary mode cutoff density of 1.0 x 10/sup 13/ cm/sup -3/. Extraordinary mode power launched obliquely from the high field side increased the temperature from 600 eV to 1200 eV with 85 kW, for densities well below the ex… more
Date: March 1, 1982
Creator: Prater, R. & Moeller, C.P.
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Partner: UNT Libraries Government Documents Department
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Shaping and characteristics of doublet plasmas in Doublet III

Description: The shaping and plasma characteristics of doublet plasmas in Doublet III with high-Z limiters are described. Typical steady-state parameters at B/sub T/ = 24 kG are I/sub p/ = 1.5 MA, V/sub loop/ = 1.6 V, T/sub e/(O) = 1.0 keV, anti n/sub e/ = 4 x 10/sup 13/ cm/sup -3/, Z/sub eff/ = 2, q(O) approx. 1 and tau /sub E//sup e/(O) = 20 msec. Electron energy confinement and maximum plasma density are in agreement with standard circular tokamak empirical scaling laws. Chromium and molybdenum appear to… more
Date: October 1, 1979
Creator: Ohkawa, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Doublet III vacuum vessel neutral beam armor

Description: The evolution of the Doublet III neutral beam armor is followed from the initial design of a radiation cooled metallic tile to the present actively cooled graphite design. Results of the thermal and stress analyses that dictated the present design are reviewed.
Date: November 1, 1979
Creator: Sevier, L.; Davis, L.; Bailey, E.; McKelvey, T. & Smith, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Application of programmable controllers to vacuum system interlocks

Description: This paper describes the Doublet III Vacuum Control System in which all input signals and output loads are connected to a programmable controller (PC) for logical interfacing. Input signals derived from CAMAC, control panels, limit switches, etc., are implemented as output signals to CAMAC, vacuum valves, pump motors, etc., according to a logic program stored in the PC memory. The memory can be easily programmed by anyone familar with either Boolean algebra or relay-ladder network diagrams. The… more
Date: November 1, 1979
Creator: Lee, G. & Moore, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design of a dee vacuum vessel for Doublet III

Description: The Big Dee modification project has completed the basic physics design and conceptual engineering design phase and is beginning detailed engineering. The project is funded in FY83 for completing most of the detailed design and placing orders for long lead components and systems. This paper summarizes the conceptual engineering design, especially of the vessel itself.
Date: January 1, 1983
Creator: Davis, L. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Outgassing measurements and results used in designing the Doublet III Neutral Beam Injector System

Description: Material vacuum properties played an important part in designing the Neutral Beam Injector System for General Atomic's Doublet III Tokamak. Low operating vacuum tank pressures were desired to keep re-ionization of the Neutral Beam to a minimum. Plasma contamination was also a major concern, hence stringent material impurity constraints were imposed. Outgassing Rate Measurement and Residual Gas Analyses were performed on different types of materials to determine if their vacuum properties were c… more
Date: November 1, 1979
Creator: Yamamoto, R.M. & Harvey, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Practical aspects of a 2-D edge-plasma model

Description: The poloidal divertor configuration is considered the most promising solution to the particle and energy exhaust problem for a tokamak reactor. The scrape-off layer plasma surrounding the core and the high-recycling plasma near the divertor plates can be modelled by fluid equations for particle, momentum and energy transport. A numerical code (B2) based on a two-dimensional multi-fluid model has been developed for the study of edge plasmas in tokamaks. In this report we identify some key featur… more
Date: July 1, 1989
Creator: Rensink, M. E.; Hill, D. N.; Porter, G. D.; Braams, B. J. (Lawrence Livermore National Lab., CA (USA) & Princeton Univ., NJ (USA). Plasma Physics Lab.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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DIII neutral beam shielding

Description: It appears that neutral beam heating will be the most viable method of raising the temperature of a plasma for some time to come. In fact, neutral beams may continue to be one stage of the heating program indefinitely. However, the external field, called the fringe field, of a Tokamak can impair the effectiveness and operation of the ion source and beam. Remember, a Tokamak is a large, air-core transformer coupled with a solenoid. The design process is summarized from start to finish. The sourc… more
Date: October 1, 1979
Creator: DeWitt, R. & Low, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Real time acquisition, processing, and archiving of Doublet III diagram data employing table driven software

Description: This paper describes the diagnostic data acquisition, processing and archiving computer system for the Doublet III fusion research device. This paper's emphasis is mainly on the software, but provides a description of the hardware configuration. (MOW)
Date: November 1, 1979
Creator: Glad, A.; Henline, P.; Gross, L. & McHarg, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Conceptual design summary for modifying Doublet III to a large dee-shaped configuration

Description: The Doublet III tokamak is to be reconfigured by replacing its indented (doublet) vacuum vessel with a larger one of a dee-shaped cross section. This change will permit significantly larger elongated plasmas than is presently possible and will allow higher plasma current (up to 5 MA) and anticipated longer confinement time. Reactor relevant values of stable beta and plasma pressure are predicted. This modification, while resulting in a significant change in capability, utilizes most of the exis… more
Date: May 1, 1983
Creator: Davis, L. G.; Gallix, R.; Luxon, J. L.; Mahdavi, M. A.; Puhn, F. A.; Rock, P. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Spatial dependence of the sheath power transmission factor in DIII-D

Description: The spatial dependence of the power transmission factor, d, associated with an ion-electron pair passing through the sheath at the DIII-D divertor plate has been determined by sweeping the edge plasma across Langmuir probe detectors. Our results show that d decreases from the classically expected value of eight near the low density edge of the scrape-off-layer plasma to values less than unity at the peak of the profile. 13 refs., 16 figs.
Date: February 1, 1991
Creator: Futch, A. H.; Hill, D. N.; Porter, G. D.; Matthews, G.F. (UKAEA Culham Lab., Abingdon (UK)) & Buchenauer, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Applying process-control techniques to a research environment: on-line controls and instrumentation for Doublet III fusion project

Description: The system design is given in terms of the following: (1) conventional aspects, (2) architecture, (3) electronic interfaces, (4) operator interfaces, (5) unconventional aspects, (6) electrical energy, (7) electrical noise, (8) operating flexibility, and (9) command procedure development. (MOW)
Date: September 1, 1983
Creator: Drobnis, D. D.
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Partner: UNT Libraries Government Documents Department
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Changes in near-surface microstructure of metallic limiters following one year of service in Doublet III

Description: The structural alloys Ta-10W, Mo, and Inconel X-750 were used for plasma limiters during the 3-MW ohmic heating experiments of the Doublet III tokamak. Post-service examinations of these limiters are reviewed. Near-surface melting, cracking, and microstructural changes are shown and discussed. During III service, elements from other metallic components were transported by the plasma and deposited on the limiter surface; significantly, high concentrations of Ni, Fe, Mo, and C were detected in th… more
Date: August 1, 1981
Creator: Trester, P. W.; Sevier, D. L. & Sabado, M. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Doublet III beamline: as-built

Description: In order to fully exploit Doublet III capabilities and to study new plasma physics regimes, a Neutral Beam Injector System has been constructed. Initially, a two beamline system will supply 7 MW of heat to the plasma. The system is currently being expanded to inject approx. 20 MW of power (6 beamlines). Each beamline is equipped with two Lawrence Berkeley Laboratory type rectangular ion sources with 10 cm x 40 cm extraction grids. These sources will accelerate hydrogen ions to 80 keV, with extr… more
Date: March 1, 1980
Creator: Harder, C.R.; Holland, M.M.; Parker, J.W.; Gunn, J. & Resnick, L.
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Partner: UNT Libraries Government Documents Department
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Function and operation of the Doublet III E-coil vacuum breaker system

Description: The ohmic heating system for the Doublet III fusion research device at General Atomic is required to provide the voltage for the initial breakdown phase (there is no preionization) along with the energy to drive the plasma current to a value of 2.5 MA or greater. This requires a peak one turn voltage of 250 volts (16 kV across coil terminals) and a magnetic flux swing of 5 volt-seconds (peak coil current of 110 kA). This voltage and flux swing is accomplished by reverse biasing the ohmic heatin… more
Date: November 1, 1979
Creator: Callis, R. W.; Jackson, G.; DeGrassie, J.; Peterson, P. & LeVine, F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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