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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Antimatter propulsion, status and prospects

The use of advanced propulsion techniques must be considered if the currently envisioned launch date of the manned Mars mission were delayed until 2020 or later. Within the next thirty years, technological advances may allow such methods as beaming power to the ship, inertial-confinement fusion, or mass-conversion of antiprotons to become feasible. A propulsion system with an ISP of around 5000 s would allow the currently envisioned mission module to fly to Mars in 3 months and would require about one million pounds to be assembled in Earth orbit. Of the possible methods to achieve this, the antiproton mass-conversion reaction offers the highest potential, the greatest problems, and the most fascination. Increasing the production rates of antiprotons is a high priority task at facilities around the world. The application of antiprotons to propulsion requires the coupling of the energy released in the mass-conversion reaction to thrust-producing mechanisms. Recent proposals entail using the antiprotons to produce inertial confinement fusion or to produce negative muons which can catalyze fusion. By increasing the energy released per antiproton, the effective cost, (dollars/joule) can be reduced. These proposals and other areas of research can be investigated now. These short term results will be important in assessing the long range feasibility of an antiproton powered engine.

Howe, Steven D.↗
NASA NTRS1999

Inertial Electrostatic Confinement Fusion: Set-Up and Operation

During the research period focus was placed upon set-up, installment, and operation of the IEC. While procurement of specific components was difficult, the IEC was on several occasions demonstrated to be practical and safe during operation. Over the course of the summer several different grids were tested and various modes were obtained. While hard data was not produced, the IEC did something more important, which was to become established here at Marshall and pave the way for future IEC systems to be built.

Hurst, Chantelle M.↗
NASA NTRS2001

Progress In Magnetized Target Fusion Driven by Plasma Liners

Magnetized target fusion (MTF) attempts to combine the favorable attributes of magnetic confinement fusion (MCF) for energy confinement with the attributes of inertial confinement fusion (ICF) for efficient compression heating and wall-free containment of the fusing plasma. It uses a material liner to compress and contain a magnetized plasma. For practical applications, standoff drivers to deliver the imploding momentum flux to the target plasma remotely are required. Spherically converging plasma jets have been proposed as standoff drivers for this purpose. The concept involves the dynamic formation of a spherical plasma liner by the merging of plasma jets, and the use of the liner so formed to compress a spheromak or a field reversed configuration (FRC).

Thio, Francis Y. C.↗
NASA NTRS2001

Magnetized Target Fusion Driven by Plasma Liners

Magnetized target fusion (MTF) attempts to combine the favorable attributes of magnetic confinement fusion (MCF) for energy confinement with the attributes of inertial confinement fusion (ICF) for efficient compression heating and wall-free containment of the fusing plasma. It uses a material liner to compress and contain a magnetized plasma. For practical applications, standoff drivers to deliver the imploding momentum flux to the target plasma remotely are required. Spherically converging plasma jets have been proposed as standoff drivers for this purpose. The concept involves the dynamic formation of a spherical plasma liner by the merging of plasma jets, and the use of the liner so formed to compress a spheromak or a field reversed configuration (FRC). For the successful implementation of the scheme, plasma jets of the requisite momentum flux density need to be produced. Their transport over sufficiently large distances (a few meters) needs to be assured. When they collide and merge into a liner, relative differences in velocity, density and temperature of the jets could give rise to instabilities in the development of the liner. Variation in the jet properties must be controlled to ensure that the growth rate of the instabilities are not significant over the time scale of the liner formation before engaging with the target plasma. On impact with the target plasma, some plasma interpenetration might occur between the liner and the target. The operating parameter space needs to be identified to ensure that a reasonably robust and conducting contact surface is formed between the liner and the target. A mismatch in the "impedance" between the liner and the target plasma could give rise to undesirable shock heating of the liner leading to increased entropy (thermal losses) in the liner. Any irregularities in the liner will accentuate the Rayleigh-Taylor instabilities during the compression of the target plasma by the liner.

Thio, Y. C. Francis↗
NASA NTRS2001

Magnetized Target Fusion: Prospects for Low-Cost Fusion Energy

Magnetized Target Fusion (MTF) has attracted renewed interest in recent years because it has the potential to resolve one of the major problems with conventional fusion energy research - the high cost of facilities to do experiments and in general develop practical fusion energy. The requirement for costly facilities can be traced to fundamental constraints. The Lawson condition implies large system size in the case of conventional magnetic confinement, or large heating power in the case of conventional inertial confinement. The MTF approach is to use much higher fuel density than with conventional magnetic confinement (corresponding to megabar pressures), which results in a much-reduced system size to achieve Lawson conditions. Intrinsically the system must be pulsed because the pressures exceed the strength of any known material. To facilitate heating the fuel (or "target") to thermonuclear conditions with a high-power high-intensity source of energy, magnetic fields are used to insulate the high-pressure fuel from material surroundings (thus "magnetized target"). Because of magnetic insulation, the required heating power intensity is reduced by many orders of magnitude compared to conventional inertial fusion, even with relatively poor energy confinement in the magnetic field, such as that characterized by Bohm diffusion. In this paper we show semi-quantitatively why MTF-should allow fusion energy production without costly facilities within the same generally accepted physical constraints used for conventional magnetic and inertial fusion. We also briefly discuss potential applications of this technology ranging from nuclear rockets for space propulsion to a practical commercial energy system. Finally, we report on the exploratory research underway, and the interesting physics issues that arise in the MTF regime of parameters. Experiments at Los Alamos are focused on formation of a suitable plasma target for compression, utilizing the knowledge base for compact toroids called Field-Reversed Configurations. As reported earlier, it appears that the existing pulsed-power Shiva Star facility at the Air Force Research Laboratory in Albuquerque, NM can satisfy the heating requirements by means of imploding a thin metal cylinder (called a "liner") surrounding an FRC of the type presently being developed. The proposed next step is an integrated liner-on-plasma experiment in which an FRC would be heated to 10 keV by the imploding liner.

Siemon, Richard E.↗
NASA NTRS1986

Physics through the 1990s: Plasmas and fluids

The volume contains recommendations for programs in, and government support of, plasma and fluid physics. Four broad areas are covered: the physics of fluids, general plasma physics, fusion, and space and astrophysical plasmas. In the first section, the accomplishments of fluid physics and a detailed review of its sub-fields, such as combustion, non-Newtonian fluids, turbulence, aerodynamics, and geophysical fluid dynamics, are described. The general plasma physics section deals with the wide scope of the theoretical concepts involved in plasma research, and with the machines; intense beam systems, collective and laser-driven accelerators, and the associated diagnostics. The section on the fusion plasma research program examines confinement and heating systems, such as Tokamaks, magnetic mirrors, and inertial-confinement systems, and several others. Finally, theory and experiment in space and astrophysical plasma research is detailed, ranging from the laboratory to the solar system and beyond. A glossary is included.

Source record↗
NASA NTRS1980

Alkali metal vapors - Laser spectroscopy and applications

The paper examines the rapidly expanding use of lasers for spectroscopic studies of alkali metal vapors. Since the alkali metals (lithium, sodium, potassium, rubidium and cesium) are theoretically simple ('visible hydrogen'), readily ionized, and strongly interacting with laser light, they represent ideal systems for quantitative understanding of microscopic interconversion mechanisms between photon (e.g., solar or laser), chemical, electrical and thermal energy. The possible implications of such understanding for a wide variety of practical applications (sodium lamps, thermionic converters, magnetohydrodynamic devices, new lasers, 'lithium waterfall' inertial confinement fusion reactors, etc.) are also discussed.

Stwalley, W. C.↗
NASA NTRS1981

Glass shell manufacturing in space

Highly-uniform, hollow glass spheres (shells), which are used for inertial confinement fusion targets, were formed from metal-organic gel powder feedstock in a vertical furnace. As a result of the rapid pyrolysis caused by the furnace, the gel is transformed to a shell in five distinct stages: (a) surface closure of the porous gel; (b) generation of a closed-cell foam structure in the gel; (c) spheridization of the gel and further expansion of the foam; (d) coalescence of the closed-cell foam to a single-void shell; and (e) fining of the glass shell. The heat transfer from the furnace to the falling gel particle was modeled to determine the effective heating rate of the gel. The model predicts the temperature history for a particle as a function of mass, dimensions, specific heat, and absorptance as well as furnace temperature profile and thermal conductivity of the furnace gas. A model was developed that predicts the gravity-induced degradation of shell concentricity in falling molten shells as a function of shell characteristics and time.

Downs, R. L.↗
NASA NTRS1982

Generation of a strong core centering force in a submillimeter compound droplet system

By amplitude-modulating the driving voltage of an acoustic levitating apparatus, a strong core centering force was generated in a submillimeter compound droplet system suspended by the radiation pressure in a gaseous medium. Depending on the acoustic characteristics of the droplet system, it was found that the technique can be utilized advantageously in the multiple-layer coating of an inertial confinement fusion pellet.

Lee, M. C.↗
NASA NTRS1982

Polymer coating of glass microballoons levitated in a focused acoustic field

Inertial confinement fusion (ICF) glass microballoons (GMBs) levitated in a focusing radiator acoustic device can be coated with liquid materials by deploying the liquid into the levitation field with a stepped-horn atomizer. The GMB can be forced to the center of the coating liquid with a strong acoustically generated centering force. Water solutions of organic polymers, UV-curable liquid organic monomers, and paraffin waxes have been used to prepare solid coatings on the surface of GMBs using this technique.

Young, A. T.↗
NASA NTRS1982

Air jet levitation furnace system for observing glass microspheres during heating and melting

A collimated hole structure air jet levitation system has been developed which can be used to levitate hollow glass microspheres used in inertial confinement fusion studies. An ellipsoidal furnace has been added to the system to provide a heating source. A video camera and a 16 mm movie camera connected to a microsphere system provide real time observation as well as permanent documentation of the experiments. Microspheres have been levitated at temperatures over 1400 C for over 10 minutes at a time.

Ethridge, E. C.↗
NASA NTRS1982

Glass shell manufacturing in space

Highly-uniform, hollow glass spheres, which are used for inertial-confinement fusion targets, are formed from metal-organic gel powder feedstock in a drop-tower furnace. The modelling of this gel-to-sphere transformation has consisted of three phases: gel thermochemistry, furnance-to-gel heat transfer, and gravity-driven degradation of the concentricity of the molten shell. The heat transfer from the furnace to the free-falling gel particle was modelled with forced convection. The gel mass, dimensions, and specific heat as well as furnace temperature profile and furnace gas conductivity, were controlled variables. This model has been experimentally verified. In the third phase, a mathematical model was developed to describe the gravity-driven degradation of concentricity in molten glass shells.

Nolen, R. L.↗
NASA NTRS1983

Surface characteristics of metallic glass spheres of Au(55)Pb(22.5)Sb(22.5)

It is pointed out that the production of metallic glasses of high atomic number is currently of considerable importance for inertial confinement fusion (ICF) target applications. In connection with the present investigation, spherules of the alloy Au(55)Pb(22.5)Sb(22.5) were produced. Metallic glass was formed on solidification. With the aid of X-ray diffraction studies, it was established that the spheres were completely amorphous. A near-surface phase separation on spheres of the metallic glass could be observed. Energy dispersive spectroscopy (EDS) measurements showed that the average composition of the surface differed from that of the bulk.

Lee, M. C.↗
NASA NTRS1985

Parametrized equation of state for electron liquids in the Singwi-Tosi-Land-Sjolander aproximation

Results are reported of a theoretical study of an equation of state for electron liquids (one-component plasmas of electrons embedded in a uniform neutralizing background of positive charges), where there is an interplay between the strong Coulomb-coupling effect and the degrees of Fermi degeneracy. Calculations are based on the Singwi-Tosi-Land-Sjolander approximation (1968). The calculated results are parametrized in the form of analytic formulas for the interaction and excess free energies, which are applicable over a wide range of parameters as long as the electrons are in a paramagnetic fluid state. Unlike the present study, earlier studies concentrated on plasmas where the Fermi degeneracy parameter tended either to zero or to infinity, thus excluding many actual plasmas (stellar interiors, heavy planets such as Jupiter, plasmas in projected inertial confinement fusion experiments, and the liquid metals).

Tanaka, S.↗
NASA NTRS1985

Applications of spherical shells

A new technique of producing hollow spheres of many materials at a very rapid rate, at very low cost, and with high reproducibility of shell diameter and wall thickness has been developed. Shells formed of metal or of other solid materials are expected to find numerous technical and industrial applications. For example, metal shells might be used as inertial confinement fusion targets, or as the principal constituents in lightweight structural materials for NASA Space Stations or DOD large antennas and mirrors, or be employed as containers for phase-change heat-storage media, or serve as containers for hazardous materials, or be employed as catalytic surface agents.

Wang, T. G.↗
NASA NTRS1988

Continuous Production Of Refractory Microballoons

Continuous process has economic and quality advantages over batch processes. Expected to produce high-quality microballoons at relatively low cost. Continuous hollow-jet process produces microballoons of refractory metal. Microballoon products made by continuous process includes inertial-confinement fusion targets, thermal insulators, lightweight composites, impact absorbers, and containers for hazardous materials.

Schilling, Christopher H.↗
NASA NTRS1987

PbO reduction and crucible reactions of 70 wt pct PbO-30 wt pct B2O3 glass

NASA has conducted an investigation of PbO-B2O3 glass with a view to PbO reduction and subsequent crucible reactions as a function of temperature and oxygen partial pressure, in order to establish the optimum processing conditions for subcentimetric glass hollow spheres applicable to inertial confinement fusion targets. The results obtained support the selection of appropriate crucible materials and oxygen partial pressure-temperature combinations that avoid phase separation from PbO reduction and/or crucible reactions.

Schilling, Christopher H.↗