flows with high gradient regions. For z-pinch plasma channel simulations, the adaption on temperature-momentum proves to be good in terms of the high mesh concentration it provides throughout the channel, where other quantities besides the temperature and momentum are also varying. Applications of ARMHD indicate the feasibility of using argon and nitrogen for plasma channels. Dissert. Abstr. N91-10731# International Centre for Theoretical Physics, Trieste (Italy). TEMPORAL BEHAVIOUR OF SELF GENERATED MAGNETIC FIELD AND ITS INFLUENCE ON INHIBITION OF THERMAL FLUX IN ICF PLASMA L. N. Jha (Tribhuvan Univ., Tripureswar, Nepal) Jun. 1989 12 p Sponsored in part by Swedish Academy of Sciences and RONAST (DE90-627478; IC-89/144) Avail: NTIS (US Sales Only) HC/MF A03 The self generated magnetic field of megagauss order is reported to play a crucial role in Inertial Confinement Fusion (ICF) target designs because of its strong influence on the transport of energy from the critical density region to the ablation layer. The inhibition of the thermal flux due to such a field, thus, affects the whole of the other phenomenon of ICF. The knowledge of the proper variation of the magnetic field may help in assigning the existing controversial value of flux limit, f. Many papers dealing with the spatial variation of such a field exist and are well documented but the study on the variation of self generated field with time is rare. Here, the spatial variation of the megagauss field generated in the corona of a wire target irradiated by a laser as well as a model to study the temporal nature of the B-field at the peak were obtained by solving the self inhibited diffusion which is regarded as the most dominant mechanism by which the thermal transport is influenced. The field exists for about ten nanoseconds even after the laser is switched off. The ratio of the two components of the thermal conductivity is also plotted against time and shows the inhibition. So, a track on the B-field variation both in space and time is necessary to keep for at least a few nanoseconds for computation of f. DOE N91-10732# Lawrence Livermore National Lab., CA. A DISTRIBUTED CONTROL AND MONITOR SYSTEM USED IN LASER FUSION RESEARCH Bobby A. Jones and Nicholas J. Selchow May 1990 10 P Presented at the International Conference and Exhibition of the Instrument Society of America, New Orleans, LA, 14-19 Oct. 1990 Revised (Contract W-7405-eng-48) (DE90-013478; UCRL-101945-Rev-2; CONF-901017-1-Rev-2) Avail: NTIS HC/MF A02 Laser Fusion research experiments require very low pressure environments to properly diagnose the plasma physics phenomena occurring during laser fusion reactions. Target chambers with very large and complex pumping systems are required to achieve and maintain these extremely low pressures. This paper describes a recently installed distributed control and monitoring system that automates the operation of these pumping systems. Through automation, this system is providing an enhanced shot rate by reducing the manpower required to ready the system for a target shot while increasing the overall safety of the system. DOE N91-10733# Lawrence Livermore National Lab., CA. ELECTROMAGNETIC PARTICLE CODES ON UNSTRUCTURED GRIDS John J. Ambrosiano, Scott T. Brandon, and Rainald Loehner (George Washington Univ., Washington, DC.) Jun. 1990 10 p Presented at the Free Lagrange Conference, Jackson Lake, WY, 3-7 Jun. 1990 (Contract W-7405-eng-48) (DE90-015187; UCRL-JC-104241; CONF-9006195-7) Avail: NTIS HC/MF A02 The most widely used computational model of collisionless plasmas is the Lagrangian-Eulerian hybrid technique known as particle-in-cell or PIC. In the electromagnetic version, Maxwell's equations are solved on an Eulerian grid and electromagnetic forces are interpolated from the grid to particle locations. Particles are then moved in Lagrangian fashion while their currents are interpolated back onto the grid to provide sources for the fields on the next cycle. There are many applications where one needs to model plasmas and electromagnetic waves inside regions of complicated shape. Traditional methods for solving Maxwell's equations employ finite differences on regular grids to replace differential operators. These methods are awkward for complicated boundary shapes, often replacing smoothly curved or slanted boundaries with stairsteps. The desire to incorporate realistic boundaries into plasma simulations is motivated by a host of situations in which proper representation of the boundary shape is expected to be critical. The approach to solving this problem is to design electromagnetic particle codes based on the use of unstructured grids. The arbitrary connectivity of unstructured grids provides the flexibility to place nodes wherever needed to fit the most complex boundary shapes. The most significant problems that must be addressed as a result of this strategy are grid generation, field solution, and particle tracking. The solutions to these problems, along with a few preliminary results, are presented. DOE A MATHEMATICAL MODEL OF THE STRUCTURE AND (Grants NAGW-1581; NSF ATM-89-00357) A three dimensional fluid model which includes the dispersive effect of electron inertia is used to study the nonlinear macroscopic plasma dynamics of small scale discrete auroral arcs within the auroral acceleration zone and ionosphere. The motion of the Alfven wave source relative to the magnetospheric and ionospheric plasma forms an oblique Alfven wave which is reflected from the topside ionosphere by the negative density gradient. The superposition of the incident and reflected wave can be described by a steady state analytical solution of the model equations with the appropriate boundary conditions. This two dimensional discrete auroral arc equilibrium provides a simple explanation of auroral acceleration associated with the parallel electric field. Three dimensional fully nonlinear numerical simulations indicate that the equilibrium arc configuration evolves three dimensionally through collisionless tearing and reconnection of the current layer. The interaction of the perturbed flow and the transverse magnetic field produces complex transverse structure that may be the origin of the folds and curls observed to be associated with small scale discrete arcs. Author N91-10735*# Hampton Inst., VA. Dept. of Physics. D. D. Venable and E. H. Choi 30 Sep. 1990 48 p (NASA-CR-187024; NAS 1.26:187024) Avail: NTIS HC/MF A03 CSCL 201 The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for the azimuthally uniform surface flashover which initiates plasma-puff under wide range of fill gas pressure of Ar, He and N2. The optimal fill gas pressure for the azimuthally uniform plasma-puff was about 120 mTorr and 450 Torr for He and N2, and between 120 mTorr and 5 Torr for Ar. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison (Contract DE-AC04-76DP-00789) (DE90-015840; SAND-90-1002C; CONF-9009192-12) Avail: NTIS HC/MF A02 The use of lasers to measure plasma properties is well known. Common methods include interferometry (density), Schlieren (gradient of density), and shadowgraphy (derivative of gradient). The diagnostic described uses a fast silicon photodiode quadrant detector with a differential amplifier to temporally detect the refraction of a CW laser by transient discharges or expansions of vapor, gas or plasma. The laser beam is refracted by the gradient of the total index of refraction due to neutral and ionized atoms (positive index) and electrons (negative index) in those discharges. The output of the circuit is a voltage proportional to the deflection angle of the laser beam through the discharge. The method is a time-resolved, quantitative, species discriminating (i.e., atoms or electrons) Schlieren technique. The diagnostic is easy to field, sensitive 1.3 + or - 0.1 to 3.3 + or - 0.1 mv/mrad depending on laser power, divergence, moment arm and circuit gain) and fast (rise time 11 (+ or -) 1 to 24 (+ or -) 1 ns depending on various circuit parameters). Diagnostic theory, and circuit design and performance is discussed. This Refractive INdex Gradient (RING) diagnostic was applied to measurements on several ion sources under development at Sandia for use on intense applied-B ion diodes in the light ion fusion program. Sources studied include different types of flashboards, a thermal evaporation lithium ion source, and a laser produced ion source. To illustrate the utility of this technique, examples of measurements on LEVIS (Laser Evaporation lon Source), a laser produced active lithium ion source is given. Measured properties include vapor/plasma production thresholds, expansion velocities, some species information, gradient profiles, and estimates of density profiles. = DOE Paul G. Weber, Kurt F. Schoenberg, John C. Ingraham, Guthrie (DE90-016442; LA-UR-90-2868; CONF-901025-3; Measurement of electrostatic and magnetic fluctuations in the ZT-40M Reversed Field Pinch (RFP) are used to estimate fluctuation driven transport. Edge electrostatic fluctuations appear to explain edge particle transport, analogously to some tokamak and stellarator observations. However, in contrast to tokamaks, electrostatic fluctuations do not explain the heat flux through the edge. Instead, transport of suprathermal electrons along fluctuating magnetic field lines constitute the major electron heat loss. Ion losses in ZT-40M appear to be dominated by charge exchange. DOE N91-10737# Sandia National Labs., Albuquerque, NM. THEORETICAL ANALYSIS OF A RUNAWAY ELECTRON SUPPRESSION DEVICE K. A. Niemer, J. G. Gilligan, C. D. Croessmann, and A. C. England (Oak Ridge National Lab., TN.) 1990 12 p Presented at the 16th Symposium on Fusion Technology, London, England, 3-7 Sep. 1990 (Contracts DE-AC04-76DP-00789; DE-AC05-84OR-21400) (DE90-015992; SAND-90-2018C; CONF-900918-1) Avail: NTIS HC/MF A03 A new runaway electron suppression paddle was designed with the PTA code package to reduce the runaway electron population in the Advanced Toroidal Facility (ATF), Oak Ridge National Laboratory. The PTA code package is a unique application of PATRAN, the Integrated TIGER Series, and ABAQUS for modeling high energy electron impact on magnetic fusion components and materials. By its nature, ATF is susceptible to runaway electron formation and confinement resulting in the production of a high level of hard x rays near the machine. Four previous stainless steel paddles proved effective in reducing the runaway electron population; however, electrons above 15 MeV have still been observed. Melting and bending were observed in each of the previous paddles, reducing their effectiveness. Scoping experiments are under way to further characterize the runaway electrons in ATF. Data from these experiments will provide insight into runaway electron damage mechanisms. Proposals for the N91-10740# Los Alamos National Lab., NM. TILT STABILITY AND COMPRESSION HEATING STUDIES OF FIELD-REVERSED CONFIGURATIONS D. J. Rej, M. Tuszewski, D. C. Barnes, G. A. Barnes, R. E. Chrien, R. E. Siemon, D. P. Taggart, R. B. Webster, B. L. Wright, and R. D. Milroy (Spectra Technology, Inc., Bellevue, WA.) et al 1990 7 p Presented at the 13th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Washington, DC, 1-6 Oct. 1990 (Contract W-7405-eng-36) (DE90-016443; LA-UR-90-2864; CONF-901025-2; IAEA-CN-53/C-4-4) Avail: NTIS HC/MF A02 tilt The first observations of internal tilt instabilities in field-reversed configurations (FRCs) are reported. Detailed comparisons with theory establish that data from an array of external magnetic probes are signatures of these destructive plasma instabilities. Theory and experiments are reconciled which suggests that grossly stable FRCS are restricted to very kinetic and elongated plasmas. Self-consistent 3-D numerical simulations demonstrate stabilization by the addition of a beam ion component. High power compression heating experiments with stable equilibrium FRCS are also reported. Plasmas formed in a tapered theta-pinch coil were translated along a guide magnetic field into a new single-turn compression coil where the external field is increased up to 7 times the initial value in 55 microsecs. Substantial heating is observed accompanied by a decrease in confinement time. DOE MODELS OF PLASMA CONFINEMENT AND HEATING IN J. D. Callen Sep. 1989 193 p (DE90-016671; UWPR-89-2) Avail: NTIS HC/MF A09 This report discusses the following topics: introduction to fusion and tokamaks; tokamak equilibria; ideal magnetohydrodynamic (MHD) stability; resistive MHD instabilities; particle orbits; classical transport in magnetized plasmas; neoclassical transport; models of anomalous transport; auxiliary heating and current-drive; plasma modelling; and tokamak fusion reactor issues and summary. DOE N91-10742# Oak Ridge National Lab., TN. PELLET INJECTOR DEVELOPMENT AT ORNL (OAK RIDGE M. J. Gouge, B. E. Argo, L. R. Baylor, S. K. Combs, D. T. Fehling, (DE90-017024; CONF-900918-4) Avail: NTIS HC/MF A02 Advanced plasma fueling systems for magnetic confinement experiments are under development at Oak Ridge National Laboratory (ORNL). The general approach is that of producing and accelerating frozen hydrogenic pellets to speeds in the kilometer-per-second range by either pneumatic (light-gas gun) or mechanical (centrifugal force) techniques. ORNL has recently provided centrifugal pellet injector for the Tore Supra tokamak and a new, simplified, eight-shot pneumatic injector for the Advanced Toroidal Facility stellarator at ORNL. Hundreds of tritium and DT pellets were accelerated at the Tritium Systems Test Assembly facility at Los Alamos in 1988 to 1989. These experiments, done in a single-shot pipe-gun system, demonstrated the feasibility of forming and accelerating tritium pellets at low (sup 3)He levels. A new, tritium-compatible extruder mechanism is being designed for longer-pulse DT applications. Two-stage light-gas guns and electron beam rocket accelerators for speeds of the order of 2 to 10 km/s are also under development. Recently, a repeating, two-stage light-gas gun accelerated 10 surrogate pellets at a 1-Hz repetition rate to speeds in the range of 2 to 3 km/s; and the electron beam rocket accelerator completed initial feasibility and scaling experiments. ORNL has also developed conceptual designs of advanced plasma fueling systems for the Compact Ignition Tokamak and the International Thermonuclear Experimental Reactor. N91-10743# Texas Univ., Austin. Inst. for Fusion Studies. TEARING MODES IN TOKAMAKS WITH LOWER HYBRID CURRENT DRIVE DOE X. Q. Xu and M. N. Rosenbluth (California Univ., San Diego, La Jolla.) Aug. 1990 22 p (Contract DE-FG05-80ET-53088) (DE90-017090; DOE/ET-53088/444; IFSR-444) Avail: NTIS HC/MF A03 The effect of current drive on the tearing modes in the semi-collisional regime is analyzed using the drift-kinetic equation. A collisional operator is developed to model electron parallel conductivity. For the pure tearing modes the linear and quasilinear growth rates in the Rutherford regimes were found to have roughly the same forms with a modified resistivity as without current drive. One interesting result is the prediction of a new instability. This instability, driven by the current gradient inside the tearing mode layer, is possibly related to MHD behavior observed in these experiments. DOE N91-10744# Texas Univ., Austin. Inst. for Fusion Studies. (Contract DE-FG05-80ET-53088) A unified theory of temperature gradient driven trapped ion modes and ballooning instabilities is developed using kinetic theory in banana regimes. All known results, such as electrostatic and purely magnetic trapped particle modes and ideal MHD ballooning modes (or shear Alfven waves) are readily derived from the single general dispersion relation. Several new results from ion-ion collision and trapped particle modification of ballooning modes are derived and discussed and the interrelationship between those modes is established. DOE N91-10745# Texas Univ., Austin. Inst. for Fusion Studies. (Contracts DE-FG05-80ET-53088; DE-FG03-88ER-53275) lon temperature gradient driven modes in the presence of ion-ion collisions in a toroidal geometry with trapped ions were studied by using a 1 2/2 d linearized gyro-kinetic particle simulation code in the electrostatic limit. The purpose is to try to understand the physics of flat density discharges, in order to test the marginal stability hypothesis. Results giving threshold conditions of L sub Ti/R sub 0, an upper bound on k sub chi, and linear growth rates and mode frequencies over all wavelengths for the collisionless ion temperature gradient driven modes are obtained. The behavior of ion temperature gradient driven instabilities in the transition from slab to toroidal geometry, with trapped ions, is shown. A Monte Carlo scheme for the inclusion of ion-ion collisions, in which ions can undergo Coulomb collisional dynamical friction, velocity space diffusion and random walk of guiding centers, was constructed. The effects of ion-ion collisions on the long wave length limit of the ion modes is discussed. DOE (Contract DE-FG02-89ER-53291) (DE90-017606; DOE/ER-53291/1) Avail: NTIS HC/MF A03 The research performed under this grant during the current year has focused on key issues with respect to turbulence and transport in toroidal confinement devices. This work includes theoretical and computational studies of electron thermal confinement which have concentrated on the role of sheared poloidal flow in suppressing turbulence and transport, trapped ion convective cell turbulence and microtearing turbulence; analytical studies of anomalous particle transport and pinch mechanisms, and comparison with experimental measurement; development of the theory of self-consistent radial transport of field-aligned momentum in the tokamak and reverse-field pinch (RFP); and work on other topics (ion temperature gradient driven turbulence, RFP fluctuation theory, coherent structures). Progress and publications in these areas are briefly summarized in this report. DOE N91-10748# Wisconsin Univ., Madison. STELLARATOR THEORY 1990 6 p (Contract DE-FG02-85ER-53201) (DE90-017607; DOE/ER-53201/T5) Avail: NTIS HC/MF A02 This report is principally concerned with explaining the progress which has been made in developing and applying our kinetic plasma model, in sufficient detail to demonstrate the main issues involved. At the end of this paper we briefly discuss work we have done in other areas of stellarator theory. DOE N91-10749# National Inst. for Fusion Science, Nagoya (Japan). THEORY OF LONGITUDINAL ADIABATIC INVARIANT IN THE HELICAL TORUS Jiro Todoroki Aug. 1990 35 p (NIFS-37; ISSN-0915-633X) Avail: NTIS HC/MF A03 The theory on the longitudinal adiabatic invariant valid for the helical magnetic field is developed on the basis of the variable transformation from the guiding center variables to the new adiabatic variables. The theory uses the Hamiltonian formalism with non canonical variables. Under the assumption that the rotational transform per period is small, the adiabatic invariant is defined by integral along the toroidal direction, not along the field line. The transition between the passing and the ripple trapped states is investigated; the jump of adiabatic invariant and other variables in the transition process is evaluated. The change of distribution function in the variable transformation is also discussed. Author N91-10750# National Inst. for Fusion Science, Nagoya (Japan). RF HELICITY INJECTION AND CURRENT DRIVE K. Hamamatsu, A. Fukuyama, S.-I. Itoh, K. Itoh, and M. Azumi (Japan Atomic Energy Research Inst., Naka.) Jul. 1990 37 p (NIFS-34; ISSN-0915-633X) Avail: NTIS HC/MF A03 The relation between (Range of Frequency) RF-driven current and wave helicity is analytically and numerically studied for tokamak plasma. The helicity conversion coefficient from the wave to the plasma is generally obtained and numerically examined for the waves in the range of ion cyclotron frequency. The wave propagation equation is solved as a boundary-value problem with one-dimensional inhomogeneities. It is shown that the wave helicity well satisfies the continuity equation. It was confirmed that the RF-helicity injection is not an identical phenomenon of the reduction of the one turn loop voltage due to the RF-driven current. Author N91-10751# National Inst. for Fusion Science, Nagoya (Japan). DIRECT EXTRACTION OF A Na(-) BEAM FROM A SODIUM PLASMA Mamiko Sasao, Hitoshi Yamaoka, Motoi Wada, and Junji Fujita (Doshisha Univ., Kyoto, Japan) Jul. 1990 18 p (NIFS-35; ISSN-0915-633X) Avail: NTIS HC/MF A03 Negative sodium ions Na(-) were extracted from a small multi-cusp ion source. A steady state sodium plasma was produced by primary electrons in a sodium gas evaporating from a metal sample placed in the discharge chamber. The Na(-) current density of 1.5 microA/sq cm was obtained from a single aperture of 1.5 mm at relatively low discharge power of about 0.4 W and filament power of 50 W. Extraction characteristics were studied by changing the plasma electrode bias. The extracted Na(-) current showed dependence on the bias voltage similar to that of H(-) or Li(-) volume production. Author momentum and energy fluxes are presented in terms of three thermodynamical forces, where the gradient of parallel flow is included. Particle and energy fluxes are driven by density gradient, temperature gradient, radial electric field and convection due to the fluctuations. Anomalous electron viscosity is found to be very small. Ion anomalous viscosity, heat conductivity and off-diagonal elements are comparable to the coefficients for electrons. The transport equations of ions show that off-diagonal element reduces the heat conductivity and even causes the anomalous heat pinch effect. Anomalous viscosity gives rise to additional heating on ions due to viscous damping. Author N91-10753 Max-Planck-Inst. fuer Physik und Astrophysik, MAGNETOSPHAERISCHER TEILSTUERME] Doris Sachsenweger Feb. 1990 177 p In GERMAN (MPE-218; ISSN-0178-0719; ETN-90-97871) Copyright Avail: Fachinformationszentrum Karlsruhe, 7514 Eggenstein-Leopoldshafen 2, Fed. Republic of Germany The existing acceleration and heating process of ions, and the modification of the relative contributions of the two sources of the plasma layer, solar wind and ionosphere, depending on the magnetic activity, are investigated. To this aim, measurements of loading and mass structure and the spectra of superthermic ions in the plasma layer are evaluated. They were taken in detail with the flying time spectrometer SULEICA on the AMPTE/IRM satellite. Two partial gale events are examined. The observations are compared to a model, in which the ions are accelerated through electric fields. The computations and the numerical calculations show that the flow variations observed through an acceleration in electric fields, either together with a scattering of Alfven wave high amplitude, or in the case of ion beams in the boundary layer, can be explained under the form of a flow layer acceleration. ESA B. M. Annaratone and N. S. J. Braithwaite 1989 8 p The use of electrostatic probes in processing plasmas which are generated by RF (13.56 MHz) excitation is addressed. The chief problems for probes in these plasmas arises from the RF fluctuations of space potential. At this operating frequency cable capacitance is a considerable load. Owing to the nonlinear nature of the probe characteristic the averaging process distorts the data. The favored solution is to ensure that the RF component of the potential between the plasma and the probe circuit is prevented from appearing across the sheath around the probe tip and also from charging the cable capacitance. Two differently designed probes were tested simultaneously in the same RF plasma discharge, and the performances are analyzed. ESA 76 SOLID-STATE PHYSICS Includes superconductivity. For related information, see also 33 Electronics and Electrical Engineering and 36 Lasers and Masers. N91-10755*# Alabama Univ., Huntsville. THE GROWTH OF ZINC SELENIDE SINGLE CRYSTALS BY PHYSICAL VAPOR TRANSPORT IN MICROGRAVITY Semiannual Status Report No. 2, 1 Nov. 1989 31 Mar. 1990 Elmer E. Anderson, Franz E. Rosenberger, and Hai-Yuin Cheng 5 Jun. 1990 23 p Original contains color illustrations (Grant NAG8-767) (NASA-CR-180428; NAS 1.26:180428) Avail: NTIS HC/MF A03; 4 functional color pages CSCL 20L Growth and characterization studies will be performed on zinc selenide single crystals. The high temperature outgassing behavior of the silica ampoule material will be studied in order to develop a cleaning and bake-out procedure that will minimize the amount of impurities introduced into the vapor from the ampoule materials and in particular during the seal-off procedure. The outgassing behavior of the ZnSe starting material will be studied during high vacuum refinement at elevated temperatures in order to develop a temperature pressure program that will optimize the removal of impurities while minimizing a shift in stoichiometry due to preferred evaporation of the higher fugacity component. The mass spectrometer system was completed, and after calibration, will be used to perform the above tasks. The system and its operation is described in detail. E.R. N91-10756# Midwest Research Inst., Golden, CO. Solar Energy ION-ASSISTED DOPING OF 2-6 COMPOUNDS DURING R. H. Bube, A. L. Farenbruch, A. Lopez-Otero, K.-F. Chien, M. (DE90-000358; SERI/TP-211-3907) Avail: NTIS HC/MF A05 This report describes a research program to (1) investigate ion-assisted doping during chemical vapor deposition of CdTe and (2) determine the influence of co-depositing ionized dopant atoms in the growth and structural and photoelectronic properties of the deposited films. In p-CdTe homo-epitaxial films, we controlled doping up to about 6 x 10(exp 16) cm(exp-3) and 2 x 10(exp 17) cm(exp-3) or ion-assisted depositions with As and P ions, respectively. At a growth rate of approximately 0.1 microns/min., a substrate temperature of 400 C, and ion energy of 60 eV, a maximum doping density was found near an ion current of 0.6 microamps/cm(exp 2). Related studies included elucidating the role of low-energy ion damage in the ion-assisted doping process, and investigating the decrease in carrier density near the surface of p-CdTe upon heating in vacuum, H(sub 2), or Ar. We demonstrate the ability to make carrier density profiles and to grade junctions, and we present preliminary results from polycrystalline p-CdTe films grown on graphite and alumina substrates. We also present solar cells prepared using the p-CdTe as the collector area and n-CdS as the window layer, and we examine their photovoltaic parameters for different carrier densities and configurations in p-CdTe. N91-10757# Argonne National Lab., IL. HIGH-TEMPERATURE SUPERCONDUCTORS: THEIR POTENTIAL FOR UTILITY APPLICATIONS DOE R. F. Giese, T. P. Sheahen, A. M. Wolsky, and D. K. Sharma (Electric Power Research Inst., Palo Alto, CA.) 1990 7 P Presented at the 1st Joint IEEE/PES International Power Meeting, New Delhi, India, 28 Oct. 1 Nov. 1990 (Contract W-31-109-eng-38) (DE90-009704; CONF-901062-1) Avail: NTIS HC/MF A02 A number of proposed applications of superconductivity for the electric utility sector are described, the current status of their development is summarized, and the potential impact of successful development of high-temperature superconductors (HTSC's) is discussed. Performance goals for development of HTSCs are presented and compared with the current status of development of HTSCs. Applications discussed include large-scale generators, motors, transmission lines, magnetic storage, transformers, power electronics, and fault-current limiters. N91-10758# Oak Ridge National Lab., TN. PREPARATION OF SUPERCONDUCTING WIRE BY DEPOSITION OF YBa2Cu30(x) ONTO FIBERS DOE W. J. Lackey, J. A. Hanigofsky, M. J. Shapiro, W. B. Carter, D. N. Hill, E. K. Barefield, E. A. Judson, D. F. OBrien, Y. S. Chung, and T. S. Moss et al 1990 16 p Presented at the 11th International Conference on Chemical Vapor Deposition, Seattle, WA, 14-19 Oct. 1990 Prepared in cooperation with Georgia Inst. of Tech., Atlanta Sponsored in part by DARPA and Navy (Contract DE-AC05-84OR-21400) (DE90-013380; CONF-901088-3) Avail: NTIS HC/MF_A03 A controllable process was developed for chemical vapor deposition of superconducting YBa2Cu30(x). The process relies on feeding and transport of a finely ground powder mixture of Y, Ba, and Cu tetramethylheptanedionates into a CVD furnace. X ray diffraction, scanning electron microscopy, analytical electron microscopy, analytical electron microscopy, resistance versus temperature, and critical current measurements have been used to characterize the films. The optimum processing parameters were determined using parametric studies involving temperature, pressure, reagent feed rate and composition, and coating time. Extensive c-axis orientation was observed using x ray diffraction and transmission electron microscopy. The presence of impurity phases and substrate coating interaction layers were observed. YBa2Cu30(x) coatings on MgO (100) single crystal substrates exhibited critical currents of 2 x 10(exp 4) A sq cm at 77 K, O Tesla, with critical temperatures of 86 K. Deposition of the YBa2Cu30(x) material onto several fibrous substrates was achieved, and a continuous fiber coating furnace is in operation. DOE N91-10759# Argonne National Lab., IL. Materials and IMPACT OF HIGH-CRITICAL-TEMPERATURE May 1990 48 P J. L. Krazinski, R. E. Holtz, and R. A. Jaross The impact is studied of the development of practical, high critical temperature superconducting materials on applications involving electromagnetic (EM) pumping. Potential improvements in the operating characteristics of EM pumps were examined for current pump technology. In addition, the study addressed whether the development of high (Tc) superconductors could enable the implementation of EM pumps in applications where it has not been previously feasible. This assessment focused on two specific types of EM pumps: helical rotor pumps with rotating field coils and EM thruster pumps for ship propulsion. The design and performance of helical rotor pumps were analyzed for both liquid metals and nonmetallic fluids. For liquid metals, the impact of superconductors on the pump size, mass, and efficiency was examined for EM pumps operating at relatively lower magnetic field strengths. For nonmetallic fluids, the study investigated whether the use of high magnetic field strengths, in conjunction with high (Tc) superconductors, could enable the pumping of these fluids with EM pumps of reasonable size and efficiency. The impact of high (Tc) superconducting materials on the reliability and economics of EM pumps was also examined. In addition, the study assessed the impact of high field strength, superconducting magnets on the feasibility of using EM thrusters for ship propulsion. Parametric studies were conducted on the effects of magnetic field strength, thruster size, vessel speed, and vessel size on the predicted thruster efficiencies. The results were compared with these of earlier studies on electromagnetic propulsion that incorporated both superconducting and nonsuperconducting magnet designs. N91-10760# Physics. DOE Brookhaven National Lab., Upton, NY. Dept. of MUON SR AND HIGH T(SUB c) SUPERCONDUCTIVITY (Contract DE-AC02-76CH-00016) (DE90-015089; BNL-44819; CONF-900489-2) Avail: NTIS HC/MF A03 Some implications of Muon Spin Rotation experiments on high temperature superconductors are discussed. The possible |