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Fabrication of superconductors. [NbTi in Cu, CuNi matrix]

Description: The paper discusses the development of a process for making high performance, fine-filament superconducting wires, utilizing dual matrix stabilization and Nb/sub 46/Ti superconducting filaments. Minimum filament size-achieved was 8 ..mu..m using OFHC copper and Cu/sub 30/Ni matrix materials. Ductility of the NbTi starting material was found to exert a major influence on the properties of the finished wire, and specifications for acceptable NbTi were developed. When specific impurity levels are exceeded, micron size precipitates and large inclusions are found. A rigorous stacking and extrusion procedure was developed. Very high density billets for extrusion were obtained by such techniques as co-drawing the stacking elements, contouring shells on a gear shaper, and hydrostatic compaction. Extrusion parameters discussed are reduction ratios, temperatures, and working speeds. (auth)
Date: January 1, 1976
Creator: Turner, W. C.; Lundberg, L. B.; Zeitlin, B.; deWinter, T. A. & McDonald, W. K.
Partner: UNT Libraries Government Documents Department

Plasma wall charge-exchange interactions in the 2XIIB magnetic mirror experiment

Description: Plasma-wall interactions by charge-exchange wall bombardment in the 2XIIB magnetic mirror experiment are discussed. Experimental measurements are modeled with a time-dependent, radial density buildup calculation. A low-density plasma sufficient to help shield the hot interior plasma from cold-gas erosion, as required by the model, is measured.
Date: January 1, 1976
Creator: Stallard, B. W.; Coensgen, F. H.; Cummins, W. F.; Gormezano, C.; Logan, B. G.; Molvik, A. W. et al.
Partner: UNT Libraries Government Documents Department

Development of coring, consolidating, subterrene penetrators

Description: Coring penetrators offer two advantages over full face-melting penetrators, i.e., formation of larger boreholes with no increase in power and the production of glass-lined, structurally undisturbed cores which can be recovered with conventional core-retrieval systems. These cores are of significant value in geological exploratory drilling programs. The initial design details and fabrication features of a 114-mm-diam coring penetrator are discussed; significant factors for design optimization are also presented. Results of laboratory testing are reported and compared with performance predictions, and an initial field trial is described.
Date: February 1, 1976
Creator: Murphy, H. D.; Neudecker, J. W.; Cort, G. E.; Turner, W. C.; McFarland, R. D. & Griggs, J. E.
Partner: UNT Libraries Government Documents Department

Electrostatic ion cyclotron waves and ion energy diffusion in a mirror machine. [2XIIb machine]

Description: Measurements of ion cyclotron fluctuations and ion energy diffusion in the neutral beam injected 2XIIB mirror machine are presented. A narrow band single mode spectrum is always observed. When the plasma is de-stabilized by turning off axially injected streaming plasma, the wave amplitude increases and a simultaneous increase in ion-energy diffusion is observed. The spectral properties of the wave do not change. The data are in accord with a wave particle saturation of the drift cyclotron loss cone (DCLC) mode.
Date: August 1, 1977
Creator: Turner, W. C.
Partner: UNT Libraries Government Documents Department

Multi-channel neutral analyzer-system

Description: Design and calibration of a 15 channel multi-channel analyzer for analysis of energetic neutral particles escaping a hot plasma are discussed. Features of the analyzer include a frequency response from DC to 50 kHz, spatial resolution, mass resolution, and data acquisition and processing for 15 points on the energy distribution that are simultaneously recorded. Another feature of the system is the ability to radially scan the plasma. An rf ion source is used to provide ions and neutrals used for calibration of a reference single channel analyzer. This analyzer is, in turn, used to calibrate the multi-channel analyzer over the energy range 500 eV to 40 keV. A brief description of the data processing system is included. (RME)
Date: September 14, 1977
Creator: Nexsen, Jr., W. E.; Turner, W. C. & Cummins, W. F.
Partner: UNT Libraries Government Documents Department

300-kJ, 200-kA Marx module for Antares

Description: Antares is a 100-kJ CO/sub 2/ laser driver for inertial confinement fusion experiments. The power amplification stage is pumped by an electron-beam-controlled gas discharge. There are 24 annular discharge regions, each requiring energy input of 250 kJ at 550 kV, in a 2-used pulse. The energy storage module chosen for this system is a single-mesh pulse-forming network. To provide sufficient energy margin each module stores 300 kJ. A prototype 300-kJ Marx has been built and tested at the Los Alamos Scientific Laboratory. This has been used as a test bed for components, triggering, and instrumentation.
Date: January 1, 1979
Creator: Riepe, K.B.; Bickford, K.J.; Jansen, J. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Tandem mirror and field-reversed mirror experiments

Description: This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.
Date: August 21, 1979
Creator: Coensgen, F.H.; Simonen, T.C. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Field reversal produced by a plasma gun

Description: Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode.
Date: April 2, 1980
Creator: Hartman, C.W.; Condit, W.; Granneman, E.H.A.; Prono, D.; Smith, A.C. Jr.; Taska, J. et al.
Partner: UNT Libraries Government Documents Department

Studies of the formation of field reversed plasma by a magnetized co-axial plasma gun

Description: The gun injects axially into a drift tank followed by a magnetic mirror. For the experiments reported here, only the guide coils outside the vacuum vessel and solenoids on the plasma gun electrodes were used; the mirror coil was not energized. A stainless steel flux conserver is placed in the mirror throat to prevent the plasma from contacting the nonconducting vacuum wall in the region of the mirror. An axis encircling array of magnetic loop probes includes four diamagnetic loops and a loop which measures the azimuthally averaged outward pointing radial component of magnetic field. These loop probes are stainless steel jacketed and form a flux conserving boundary (at a radius = 30 cm) for plasma emitted from the gun. A five tip probe that can be positioned anywhere along the axis of the experiment is used to measure internal components of magnetic field.
Date: May 28, 1980
Creator: Turner, W.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J. & Smith, A.C. Jr.
Partner: UNT Libraries Government Documents Department

Introduction to magnetic confinement fusion diagnostics

Description: These notes present a brief survey of some of the current diagnostic techniques used in magnetic fusion plasma devices. To give an idea of the range of parameters and geometries encountered the parameters of four representative experiments - PLT, TMX, ZT-40 and EBT-I(S) - are given. The central issue of all experiments is to understand the flow of power which can be summarized by two volume integrated equations for the ions and electrons.
Date: June 6, 1980
Creator: Turner, W.C.
Partner: UNT Libraries Government Documents Department

Formation of compact toroidal plasmas by magnetized coaxial plasma gun injection into an oblate flux conserver

Description: Initial results are reported on the formation of compact toroidal plasmas in an oblate shaped metallic flux conserver. A schematic of the experimental apparatus is shown. The plasma injector is a coaxial plasma gun with solenoid coils wound on the inner and outer electrodes. The electrode length is 100 cm, the diameter of the inner (outer) electrode is 19.3 cm (32.4 cm). Deuterium gas is puffed into the region between electrodes by eight pulsed valves located on the outer electrode 50 cm from the end of the gun. The gun injects into a cylindrically symmetrical copper shell (wall thickness = 1.6 mm) which acts as a flux conserver for the time scale of experiments reported here. The copper shell consists of a transition cylinder 30 cm long, 34 cm in diameter, a cylindrical oblate pill box 40 cm long, 75 cm in diameter and a downstream cylinder 30 cm long, 30 cm in diameter. The gap between the gun and transition cylinder is 6 cm. An axial array of coils outside the vacuum chamber can be used to establish an initial uniform bias field.
Date: November 4, 1980
Creator: Turner, W.C.; Goldenbaum, G.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J. et al.
Partner: UNT Libraries Government Documents Department

Computational compact torus experiment

Description: We describe a typical 2D magnetohydrodynamic (MHD) calculation of rundown of plasma in a coaxial, magnetized gun and injection of the plasma and reconnection of the embedded magnetic fields to form a compact toroidal plasma.
Date: December 24, 1980
Creator: Eddleman, J.L.; McNamara, B.; Nash, J.K.; Shearer, J.W. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Numerical simulation of the Beta II experiment

Description: The transport code FRT which is a 1-1/2-D transport-equilibrium code for an axisymmetric plasma was used to simulate the decay of the plasma and magnetic fields of the Beta II experiment. A comparison is made between the experimentally determined decay times for the magnetic fields and particle confinement times and the computed decay times. It is found that 1% oxygen impurity is enough to clamp the electron temperature below the radiation barrier, which is in agreement with the experiment.
Date: October 1, 1981
Creator: Shumaker, D.E.; Boyd, J.K.; McNamara, B. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Laser-plasma interaction experiments at laser wavelengths of 1. 064. mu. m, 0. 532. mu. m and 0. 355. mu. m

Description: Experiments at all three wavelengths included the following: target absorption, stimulated Brillouin scattering, suprathermal electron production, observation of harmonic and half harmonic emission from the plasma as a signature of parametric processes such as 2..omega../sub pe/ and simulated Raman scattering. These experiments are presented and compared with detailed hydro code and plasma simulation results.
Date: January 1, 1982
Creator: Campbell, E.M.; Mead, W.C. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Plasma-Parameter Measurements Using Neutral-Particle-Beam Attenuation

Description: Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure neutral-beam attenuation along chords through the plasma volume at different radial and axial positions. The radial array is used to infer the radial plasma-density profile; the axial array, to infer the axial plasma-density profile and the ion angular distribution at the plasma midplane.
Date: July 7, 1982
Creator: Foote, J. H.; Molvik, A. W. & Turner, W. C.
Partner: UNT Libraries Government Documents Department

Experimental observations and model calculations of impurity radiation in a plasma gun compact torus experiment

Description: Several types of radiation measurements were performed on the Beta II compact forms experiment. Among these are time integrated spectra ranging in wavelength from the vuv to the uv, time resolved bolometer measurements of radiation from the x-ray to the infrared, and time and wavelength resolved measurements of certain spectral lines. It is difficult to relate any one of these measurements to plasma parameters of interest such as temperature, density, or impurity content. In this report we compare the results of these, and other measurements with two simple models of the power balance in the plasma in order to estimate the effect of carbon and oxygen impurities on plasma lifetime.
Date: August 10, 1982
Creator: Goldenbaum, G.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Dynamic gas flow during plasma operation in TMX-U

Description: Control of the neutral density outside of the plasma radius is essential for proper operation of the various plasma configurations in TMX-U. TMX-U excess-beam, stream-gun, gas-box, and beam-reflux gases are pumped internally in regions defined by 73/sup 0/ Ti-gettered liners and warm Ti-gettered plasma liners. The array of fast and slow ion gauges - a large TMX-U diagnostic - has been used to measure the dynamic pressure in many of the liner-defined regions on three time scales. The natural divertor action, or plasma pump effect, of mirror plasmas has been measured using the ion gauge diagnostics on a fast time scale during operation of TMX-U with ECRH start-up. Routine operation of TMX-U is enhanced by the ability to verify the effectiveness of gettering and to locate leaks using pressure data collected on the two slow time scales. A computer code, DYNAVAC 6, which treats TMX-U as a set of conductance-coupled regions with pumping and sources in each region, has been used to successfully model the overall gas dynamics during all phases of TMX-U operation.
Date: November 12, 1982
Creator: Pickles, W.L.; Carter, M.R.; Clower, C.A.; Drake, R.P.; Hunt, A.L.; Simonen, T.C. et al.
Partner: UNT Libraries Government Documents Department

Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

Description: The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal-barrier experiments designed to provide an improved performance for tandem-mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering system.
Date: August 12, 1983
Creator: Calderon, M.O.; Hunt, A.L.; Lang, D.D.; Nexsen, W.E.; Pickles, W.L. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Control of gas input and background pressure in the end plug regions of the TMX-U thermal barrier experiment

Description: Rate equations for the plasma species in a thermal barrier end plug establish an upper bound on the neutral pressure (P) external to the plasma. For the Tandem Mirror Experiment-Upgrade (TMX-U), this bound is P less than or equal to 0.5 - 1.0 x 10/sup -6/ Torr. Initially TMX-U did not satisfy this criterion, and axial end plugging of plasma losses seemed limited by the excessive pressure. Subsequently, we modified the machine to improve the vacuum conditions, decreasing P to the desired range. At the same time axial end plugging of plasma losses increased to the duration of neutral beam injection and ECRH heating. Here we summarize our experimental measurements of gas input.
Date: October 26, 1983
Creator: Turner, W.C.; Nexsen, W.E.; Allen, S.L.; Hooper, E.B.; Hunt, A.L.; Lang, D.D. et al.
Partner: UNT Libraries Government Documents Department

Tandem mirror experiment-upgrade vacuum system: a new configuration and operating parameters

Description: The Tandem Mirror Experiment-Upgrade (TMX-U) vacuum system has been installed and operating since December 1981. In 1982 and early 1983 the performance of the internal, dynamic pumping system was evaluated during physics experiments. The plasma region gas loads caused the pressure to exceed that allowable for achieving thermal barrier plasmas. The unified, multiple-beamline concept used on TMX-U to pump the neutral-beam injector gas was modified. The modifications to the system were designed to reduce conductance between the injectors and the plasma region to better use the differential pumping in the pumping regions. The modifications made were a smaller cross section neutralizer, replacing apertures with ducts between regions, eliminating the injector scrape-off in the plasma region, relocating the neutral beam dumps, and eliminating the gaps around various penetrations.
Date: December 2, 1983
Creator: Lang, D.D.; Calderon, M.O.; Hunt, A.; Nexsen, W.E.; Pickles, W.L. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Improvement of tubulars used for fracturing in hot dry rock wells

Description: Completion of hot dry rock wells as it is currently envisioned, requires that hydraulic fracturing be used to develop a heat extraction reservoir and to provide low impedance flow paths between the designated water injection and production wells. Recent fracturing operations at measured depths from 11,400 ft to 15,300 ft at the Fenton Hill Hot Dry Rock Geothermal Test Site have resulted in numerous failures of tubulars caused by the high fracturing pressures, corrosive environment and large treatment volumes at high flow rates. Two new fracturing strings were designed and purchased. Physical and chemical properties exceeding API specifications were demanded and supplied by the manufacturers. These tubulars have performed to design specifications.
Date: April 1, 1984
Creator: Nicholson, R.W.; Dreesen, D.S. & Turner, W.C.
Partner: UNT Libraries Government Documents Department

Low energy neutral source for fueling the central cell core plasma of TMX-U

Description: The performance of a low energy neutral source formed by negatively biased plates inserted in the edge plasma of the central cell of the Tandem Mirror Experiment-Upgrade (TMX-U) is described. This technique promises to be capable of fueling the high density thermal barrier plasmas. We have found that annular ring electrodes mounted on the sides of the central cell gas box and inclined 45/sup 0/ to the plasma axis can produce about 80 A of inward-directed D/sup 0/ with an average energy E/sub 0/ approx. = 250 eV (where the plate bias = -400 V). This example was calculated for a peak plasma density n/sub e/(0) = 10/sup 13/ cm/sup -3/ and an edge plasma density n/sub L/ = 10/sup 12/ cm/sup -3/ at the limiter edge defined by the biased plates. The energetic neutrals, attenuated by about an e-fold in reaching the plasma center, are thus much more efficient in fueling the core plasma than Frank-Condon atoms, which are attenuated by greater than a factor of 100. In addition, because their energy is greater than Frank-Condon atoms their initial collisional trapping rate in the thermal barrier is reduced by a factor of approximately (100)/sup 3/2/ = 1000.
Date: April 23, 1984
Creator: Turner, W.C.
Partner: UNT Libraries Government Documents Department