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Compact torus accelerator: a driver for ICF. Revision 1 (open access)

Compact torus accelerator: a driver for ICF. Revision 1

We have carried out further investigations of technical issues associated with using a compact torus (CT) accelerator as a driver for inertial confinement fusion (ICF). In a CT accelerator, a magnetically-confined torus-shaped plasma is compressed, accelerated and focused by two concentric electrodes. Here, we evaluate an accelerator point design with a capacitor bank energy of 9.2 MJ. Modeled by a O-D code, the system produces a xenon plasma ring with a radius of 0.73 cm, a velocity of 4 x 10/sup 7/ m/s, and a mass of 4.4 ..mu..g. The plasma ring energy available for fusion is 3.8 MJ, a 40% driver efficiency. Ablation and magnetic pressures of the point design, a due to CT acceleration, are analyzed. Pulsed-power switching limitations and driver cost analysis are also presented. Our studies confirm the feasibility of producing a ring to induce fusion with acceptable gain. However, some uncertainties must be resolved to establish viability.
Date: July 31, 1986
Creator: Tobin, M. T. & Morse, E. C.
System: The UNT Digital Library
ICF drivers: a comparison of some new entries and old standbys. Revision 1 (open access)

ICF drivers: a comparison of some new entries and old standbys. Revision 1

There has been a great deal of progress in recent years on the development of solid state and KrF lasers, light ion diodes, and heavy ion accelerators for use as drivers in inertial confinement fusion (ICF) facilities. Two relatively new entries in the ICF driver derby are the free electron laser (FEL) and the compact torus (CT). The status and remaining technological challenges of each potential driver are described. The author discusses driver performance criteria for various reactor applications and then gives his informed opinion in a qualitative rating of the six drivers for each application.
Date: July 31, 1986
Creator: Hogan, W.J.
System: The UNT Digital Library
Turbostar: an ICF reactor using both direct and thermal power conversion. Revision 1 (open access)

Turbostar: an ICF reactor using both direct and thermal power conversion. Revision 1

Combining direct and thermal power conversion results in a 52% gross plant efficiency with DT fuel and 68% with advanced DD fuel. We maximize the fraction of fusion-yield energy converted to kinetic energy in a liquid-lithium blanket, and use this energy directly with turbine generators to produce electricity. We use the remainder of the energy to produce electricity in a standard Rankine thermal power conversion cycle.
Date: July 31, 1986
Creator: Pitts, J.H.
System: The UNT Digital Library
Control of beam dynamics in high energy induction linacs (open access)

Control of beam dynamics in high energy induction linacs

The Advent of laser-ion-guiding in the Advanced test Accelerator along with the development of accelerator cavities optimized with respect to beam breakup coupling impedence now make it possible to consider a new class of high current, high emergy linear induction accelerators. The control of the beam breakup and other instabilities by laser guiding and by various magnetic focusing schemes will be discussed along with the scaling laws for the design of such machines to minimize the growth of the beam breakup instability. Many linacs, particularly induction linacs are limited in performance by the beam breakup (BBU) instability. The instability is found in two forms. In the first form the accelerating cavities communicate with one another through interaction with the beam and through propagation of cavity fields through the accelerator structure. In the second form which is the more virulent of the two, the cavities couple to each other only through their interactions with the beam. It is this second form of PPU that will be discussed in this paper.
Date: July 29, 1986
Creator: Caporaso, G.J.
System: The UNT Digital Library
Production of muons for fusion catalysis in a magnetic mirror configuration. Revision 1 (open access)

Production of muons for fusion catalysis in a magnetic mirror configuration. Revision 1

For muon-catalyzed fusion to be of practical interest, a very efficient means of producing muons must be found. We describe a scheme for producing muons that may be more energy efficient than any heretofore proposed. There are, in particular, some potential advantages of creating muons from collisions of high energy tritons confined in a magnetic mirror configuration. If one could catalyze 200 fusions per muon and employ a uranium blanket that would multiply the neutron energy by a factor of 10, one might produce electricity with an overall plant efficiency (ratio of electric energy produced to nuclear energy released) approaching 30%. One possible near term application of a muon-producing magnetic-mirror scheme would be to build a high-flux neutron source for radiation damage studies. The careful arrangement of triton orbits will result in many of the ..pi../sup -/'s being produced near the axis of the magnetic mirror. The pions quickly decay into muons, which are transported into a small (few-cm-diameter) reactor chamber producing approximately 1-MW/m/sup 2/ neutron flux on the chamber walls, using a laboratory accelerator and magnetic mirror. The costs of construction and operation of the triton injection accelerator probably introduces most of the uncertainty in the viability of this …
Date: July 25, 1986
Creator: Moir, R.W. & Chapline, G.F. Jr.
System: The UNT Digital Library
Infrared thermographic study of laser ignition (open access)

Infrared thermographic study of laser ignition

Pyrotechnic ignition has been studied in the past by making a limited number of discrete temperature-time observations during ignition. Present-day infrared scanning techniques make it possible to record thermal profiles, during ignition, with high spacial and temporal resolution. Data thus obtained can be used with existing theory to characterize pyrotechnic materials and to develop more precise kinetic models of the ignition process. Ignition has been studied theoretically and experimentally using various thermal methods. It has been shown that the whole process can, ideally, be divided into two stages. In the first stage, the sample pellet behaves like an inert body heated by an external heat source. The second stage is governed by the chemical reaction in the heated volume produced during the first stage. High speed thermographic recording of the temperature distribution in the test sample during laser ignition makes it possible to calculate the heat content at any instant. Thus, one can actually observe laser heating and the onset of self-sustained combustion in the pellet.
Date: July 21, 1986
Creator: Mohler, J.H. & Chow, C.T.S.
System: The UNT Digital Library
Matter oscillations and solar neutrinos: A review of the MSW (Mikheyev-Smirnov-Wolfenstein) effect (open access)

Matter oscillations and solar neutrinos: A review of the MSW (Mikheyev-Smirnov-Wolfenstein) effect

We review the theory of the Mikheyev-Smirnov-Wolfenstein effect, in which matter oscillations can greatly enhance ''in vacuo'' neutrino oscillations, and we examine its consequences for the solar neutrino problem. Using a two-flavor model, we discuss the solutions in the ..delta..m/sup 2/-sin/sup 2/2THETA parameter space for the /sup 37/Cl experiment, and describe their predictions for the /sup 71/Ga experiment and for the spectrum of electron-neutrinos arriving at earth. We also comment on the three-flavor case.
Date: July 16, 1986
Creator: Rosen, S. P. & Gelb, J. M.
System: The UNT Digital Library
Glass Making Technology for High-Level Nuclear Waste (open access)

Glass Making Technology for High-Level Nuclear Waste

This paper addresses specific and unique chemical engineering aspects of the Defense Waste Processing Facility (DWPF) at the Savannah River Plant. This paper also addresses the glass melter and those processes that are directly coupled to it. A somewhat disproportionate emphasis is given to sludge pretreatment, for the sake of completeness in this session. We have attempted to focus on those features of the DWPF that may be of general interest or even useful to the practicing chemical engineer.
Date: July 10, 1986
Creator: Boersma, M. D. & Mahoney, J. L.
System: The UNT Digital Library
The Savannah River Site and the Processing Facility Being Built to Prepare its Radioactive Waste for Permanent Disposal (open access)

The Savannah River Site and the Processing Facility Being Built to Prepare its Radioactive Waste for Permanent Disposal

This presentation provides an appreciation for the tremendous chemical processing challenges met in the development of the Defense Waste Process Facility (DWPF) process. The DWPF is presently under construction and is due for completion in 1989. Before radioactive waste is introduced to the DWPF in late 1989, the remote operation of all equipment and all process steps must be demonstrated.
Date: July 10, 1986
Creator: Knight, J. R.
System: The UNT Digital Library
Scaling of current density, total current, emittance, and brightness for hydrogen negative ion sources (open access)

Scaling of current density, total current, emittance, and brightness for hydrogen negative ion sources

The atomic and molecular processes that play a principal role in negative ion formation in a hydrogen negative ion discharge are discussed. The collisions of energetic electrons with gas molecules within the discharge lead to vibrationally excited molecules. Thermal electrons in turn attach to these excited molecules and generate negative ions via the dissociative attachment process. A system geometry chosen to optimize these collision processes is discussed that consists of a high-power discharge in tandem with a low electron temperature bath, the two regions separated by a magnetic filter. The current density extracted from such a system is found to scale inversely with the system scale length provided the gas density and electron density are also increased inversely with scale length. If a system is scaled downward in size to provide a new beamlet but one with increased current density, and these beamlets are packed to fill the original dimension, the new total extracted current will exceed the original total current by the scale factor. The emittance, epsilon, of the new system remains unchanged. The brightness, J/epsilon/sup 2/, of the new system will also be increased in proportion to the scale factor. 4 refs., 2 figs.
Date: July 10, 1986
Creator: Hiskes, J.R.
System: The UNT Digital Library
High field superconducting magnets (12 T and greater) for fusion applications (open access)

High field superconducting magnets (12 T and greater) for fusion applications

The technology for producing high fields in large superconducting magnets has increased greatly in recent years, but must increase still more in the future. In this paper, we examine the present state of the art vis-a-vis the needs of a next-generation fusion machine and outline a program to provide for those needs. We also highlight recent developments that suggest the program goals are within reach.
Date: July 9, 1986
Creator: Miller, J. R.; Summers, L. T. & Kerns, J. A.
System: The UNT Digital Library
Performance evaluation of the HEP, ELXSI and CRAY X-MP parallel processors on hydrocode test problems (open access)

Performance evaluation of the HEP, ELXSI and CRAY X-MP parallel processors on hydrocode test problems

Parallel programming promises improved processing speeds for hydrocodes, magnetohydrocodes, multiphase flow codes, thermal-hydraulics codes, wavecodes and other continuum dynamics codes. This paper presents the results of some investigations of parallel algorithms on three parallel processors: the CRAY X-MP, ELXSI and the HEP computers. Introduction and Background: We report the results of investigations of parallel algorithms for computational continuum dynamics. These programs (hydrocodes, wavecodes, etc.) produce simulations of the solutions to problems arising in the motion of continua: solid dynamics, liquid dynamics, gas dynamics, plasma dynamics, multiphase flow dynamics, thermal-hydraulic dynamics and multimaterial flow dynamics. This report restricts its scope to one-dimensional algorithms such as the von Neumann-Richtmyer (1950) scheme.
Date: July 7, 1986
Creator: Liebrock, L. M.; McGrath, J. F. & Hicks, D. L.
System: The UNT Digital Library
Theoretical and observational review of results on nova explosions occurring on ONeMg white dwarfs (open access)

Theoretical and observational review of results on nova explosions occurring on ONeMg white dwarfs

The nova outburst is the second most violent explosion that occurs in a galaxy. This review presents the recent observational and theoretical studies that have demonstrated that there exist two classes of nova outburst. One type of nova occurs on a CO white dwarf and the other type of nova occurs on an ONeMg white dwarf. The second class of outbursts are much more violent and occur much more frequently then the first class of outbursts. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations. 51 refs.
Date: July 7, 1986
Creator: Starrfield, S.
System: The UNT Digital Library
Using nonradial pulsations to determine the envelope composition of very evolved stars (open access)

Using nonradial pulsations to determine the envelope composition of very evolved stars

Recent observational and theoretical studies of the ZZ Ceti variables (DA degenerate dwarfs), the DBV variables (DB degenerate dwarfs), and the GW Vir variables (DO degenerate dwarfs) have shown them to be pulsating in nonradial g/sup +/-modes. The pulsation mechanism has been identified for each class of variable star and, in all cases, involves predictions of the stars envelope composition. The ZZ Ceti variables must have pure hydrogen surface layers, the DBV stars must have pure helium surface layers, and the GW Vir stars must have carbon and oxygen rich surface layers. 44 refs.
Date: July 7, 1986
Creator: Starrfield, S.
System: The UNT Digital Library
Progress and prospects for soft x-ray lasing driven by high power optical lasers (open access)

Progress and prospects for soft x-ray lasing driven by high power optical lasers

We will describe our optical laser pumped xuv Laser Program. To date, we have concentrated our efforts on exploding foil amplifier designs using Ne-like n=3p to 3s inversion schemes. We will describe our latest modeling results as well as measurements which demonstrate output power near the 1 MW level at 206 and 209 A and lasing at wavelengths as short as 106 A.
Date: July 3, 1986
Creator: Rosen, M.D.; Matthews, D.L. & Hagelstein, P.L.
System: The UNT Digital Library
Accelerator and final focus model for an induction Linac based HIF system study (open access)

Accelerator and final focus model for an induction Linac based HIF system study

An overview of the assumptions and models incorporated in the ongoing Induction-Linac-based, HIF System Assessment is presented. Final transport, compression and final focus pose constraints which form a critical link between the accelerator and target requirements. A recent analysis has shown that system costs may be considerably reduced by the use of multiply charges ions. The assumptions underlying this direction are described.
Date: July 1, 1986
Creator: Lee, Edward P.
System: The UNT Digital Library
Advanced concepts for acceleration (open access)

Advanced concepts for acceleration

Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)
Date: July 1, 1986
Creator: Keefe, D.
System: The UNT Digital Library
Anomalous dimensions of multiquark bound states (open access)

Anomalous dimensions of multiquark bound states

The evolution of six-quark color-singlet state distribution amplitudes is formulated as an application of perturbative quantum chromodynamics to nuclear wave functions. We present a general method of solving the evolution equation for multiquark bound states and predict the asymptotic Q/sup 2/ slope for the deuteron charge form factor as a result.
Date: July 1, 1986
Creator: Ji, Cheung-Ryong
System: The UNT Digital Library
Comparison of q anti qg and q anti q. gamma. events in e/sup +/e/sup -/ annihilation at PEP (open access)

Comparison of q anti qg and q anti q. gamma. events in e/sup +/e/sup -/ annihilation at PEP

In comparing the particle flow in the event plane of three-jet (q anti qg) events and of radiative annihilation events (q anti q..gamma..) for similar kinematic configurations, two PEP experiments find a significant decrease in particle density in the angular region opposite to the gluon jet in q anti qg events, relative to the particle density in the region opposite to the photon in q anti q..gamma.. events. The effect is predicted both by QCD and by phenomenological string models. 5 refs., 5 figs.
Date: July 1, 1986
Creator: Hofmann, W.
System: The UNT Digital Library
Conformal invariance on Calabi-Yau spaces (open access)

Conformal invariance on Calabi-Yau spaces

The possibility of superstring compactification on Calabi-Yau manifolds is analyzed. Despite the apparent non-zero ..beta.. function at four loop order, it is possible to construct a conformally invariant sigma model on a Calabi-Yau manifold. The background metric is not Ricci flat, but is related to the Ricci flat metric through a (non-local) field redefinition. 9 refs.
Date: July 1, 1986
Creator: Nemeschansky, D.
System: The UNT Digital Library
Converging xenon shock waves driven by megagauss magnetic fields (open access)

Converging xenon shock waves driven by megagauss magnetic fields

We attempted to implode a conducting metal linear at high velocity, and our failure to do so led to switching, or rapidly transferring the field from pushing an aluminum conductor to snow-plowing a half-atmosphere of xenon gas. We successfully initiated convergent xenon gas shocks with the use of a magnetohydrodynamic switch and coaxial high-explosive, flux-compression generators. Principal diagnostics used to study the imploding xenon gas were /sup 133/Xe radioactive tracers, continuous x-ray absorption, and neutron output. We compressed the xenon gas about five to sixfold at a velocity of 10 cm/..mu..s at a radius of 4 cm. The snowplow efficiency was good; going from 13- to 4-cm radius, we lost only about 20% of the mass. The temperature of the imploded sheath was determined by mixing deuterium with the xenon and measuring the neutron output. Using reasonable assumptions about the amount, density, and uniformity of the compressed gas, we estimate that we reached temperatures as high as 155 eV. Energy-loss mechanisms that we encountered included wall ablation and Taylor instabilities of the back surface.
Date: July 1, 1986
Creator: Shearer, J. W. & Steinberg, D. J.
System: The UNT Digital Library
Coupled-channel analysis of neutron scattering from /sup 12/C between 9 and 15 MeV (open access)

Coupled-channel analysis of neutron scattering from /sup 12/C between 9 and 15 MeV

A deformed and energy dependent phenomenological optical model potential and coupled-channel formalism for deformed nuclei have been used in the analysis of elastic and inelastic (Q = 4.439 MeV) scattering, and analyzing power for neutrons scattered from /sup 12/C in the energy range of 9 to 15 MeV. 6 refs., 1 fig., 1 tab.
Date: July 1, 1986
Creator: Hansen, L. F. & Meigooni, A. S.
System: The UNT Digital Library
Cumulative releases of radionuclides from uncontained waste packages (open access)

Cumulative releases of radionuclides from uncontained waste packages

This report describes mathematical predictions for the migration of radionuclides from an emplaced radioactive waste container. The model assumes a spherical-equivalent waste solid surrounded by backfill but neglects the effect of decay heat. 7 refs., 2 tabs. (TEM)
Date: July 1, 1986
Creator: Lee, W. W. L.; Kim, C. L.; Chambre, P. L. & Pigford, T. H.
System: The UNT Digital Library
DC septum magnets for the damping rings of the SLC SLAC Linear Collider (open access)

DC septum magnets for the damping rings of the SLC SLAC Linear Collider

The injection/extraction systems of the 1.21 GeV Stanford Linear Collider (SLC) damping rings uses four pairs of water cooled septum magnets. Each pair consists of a thin-septum, low-field (3 mm, 3 kilogauss) magnet plus a thick-septum, high-field (12 mm, 8 kilogauss) model. In the latest design cooling reliability was improved by using stainless-steel tubing imbedded in the copper. The operating current in each is 2600 amperes, at a density of up to 120 amperes per mmS. Plasma-sprayed alumina is used to provide electrical insulation. The magnet system is compatible with 10 Z torr ultra-high vacuum. The magnet design, fabrication, and measurements are described.
Date: July 1, 1986
Creator: Bijleveld, J.; Peterson, J. M. & Jensen, D.
System: The UNT Digital Library