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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 55 records · Page 3

Simulation studies of plasma waves in the electron foreshock - The generation of Langmuir waves by a gentle bump-on-tail electron distribution

Particle simulation experiments were used to study the basic physical ingredients needed for building a global model of foreshock wave phenomena. In particular, the generation of Langmuir waves by a gentle bump-on-tail electron distribution is analyzed. It is shown that, with appropriately designed simulations experiments, quasi-linear theory can be quantitatively verified for parameters corresponding to the electron foreshock.

Dum, C. T.↗

Physics and astrophysics from a lunar base; Proceedings of the 1st NASA Workshop, Stanford, CA, May 19, 20, 1989

The present conference on physics and astrophysics from a lunar base encompasses space physics, cosmic ray physics, neutrino physics, experiments in gravitation and general relativity, gravitational radiation physics, cosmic background radiation, particle astrophysics, surface physics, and the physics of gamma rays and X-rays. Specific issues addressed include space-plasma physics research at a lunar base, prospects for neutral particle imaging, the atmosphere as particle detector, medium- and high-energy neutrino physics from a lunar base, muons on the moon, a search for relic supernovae antineutrinos, and the use of clocks in satellites orbiting the moon to test general relativity. Also addressed are large X-ray-detector arrays for physics experiments on the moon, and the measurement of proton decay, arcsec-source locations, halo dark matter and elemental abundances above 10 exp 15 eV at a lunar base.

Potter, A. E.↗

Physical dosimetric evaluations in the Apollo 16 microbial response experiment

Texts of high-energy multicharged particle, ultraviolet light, and galactic irradiation fluxes on exposed biological specimens aboard Apollo 16 are described. Passive nuclear track detectors, passive dosimeters, and thermoluminescent dosimeters, respectively, were used for the measurements. Biological phenomena studied ranged from lipolytic alpha toxin production in Bacillus thuringiensis to animal tissue invasion (of human hair by Trichophyton terrestre). Fluxes observed were lower than those recorded by detectors located in the Biostack and in the passive personnel dosimeters worn by the astronauts, suggesting a greater average shielding in the latter two environments.

Taylor, G. R.↗

Light scattering calculations for the nephelometer experiment on the 1981/1982 Jupiter Orbiter-Probe mission

A variety of studies were carried out to help establish the accuracy of quantities describing physical characteristics of cloud particles (such as size, shape, and composition) that are to be inferred from light scattering data obtained with the nephelameter experiment on the Galileo spacecraft. The objectives were to provide data for validating and testing procedures for analyzing the Galileo nephelameter data with light scattering observations in a variety of on-going laboratory and field measurement programs for which simultaneous observations of the physical characteristics of the scattering particles were available.

Grams, G. W.↗

Report on Active and Planned Spacecraft and Experiments

Active and planned spacecraft activity and experiments between June 1, 1980 and May 31, 1981 known to the National Space Science Data Center are described. The information covers a wide range of disciplines: astronomy, Earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. Each spacecraft and experiment is described and its current status presented. Descriptions of navigational and communications satellites and of spacecraft that contain only continuous radio beacons used for ionospheric studies are specifically excluded.

Vostreys, R. W.↗

Microgravity particle research on the Space Station - The gas-grain simulation facility

In the gravitational field on earth, the large settling rate of micron-sized particles and the effects of gravity-induced convection prohibit many interesting studies of phenomena such as coagulation, collisions, and mutual interactions of droplets, dust grains and other particles. Examples of exobiology experiments involving these phenomena are the simulation of organic aerosol formation in Titan's atmosphere, studies of the role of comets in prebiotic chemical evolution, and simulations of carbon grain interactions in various astrophysical environments. The Gas-Grain Simulation Facility (GGSF) is a proposed earth-orbital laboratory that will allow present ground-based experimental programs which study processes involving small particles and weak interactions to be extended to a new domain. Physics issues that scientists wishing to propose GGSF experiments must consider are reviewed in this paper. Specifically, coagulation, motion in gases and vacua, and wall deposition of particles in a microgravity environment are discussed.

Fogleman, G.↗

Physics of windblown particles

A laboratory facility proposed for the Space Station to investigate fundamental aspects of windblown particles is described. The experiments would take advantage of the environment afforded in earth orbit and would be an extension of research currently being conducted on the geology and physics of windblown sediments on earth, Mars, and Venus. Aeolian (wind) processes are reviewed in the planetary context, the scientific rational is given for specific experiments to be conducted, the experiment apparatus (the Carousel Wind Tunnel, or CWT) is described, and a plan presented for implementing the proposed research program.

Greeley, Ronald↗

Colloidal Disorder-Order Transition Experiment Probes Particle Interactions in Microgravity

Everything in the universe is made up of the same basic building blocks - atoms. All physical properties of matter such as weight, hardness, and color are determined by the kind of atoms present and the way they interact with each other. The Colloidal Disorder-Order Transition (CDOT) shuttle flight experiment tested fundamental theories that model atomic interactions. The experiment was part of the Second United States Microgravity Laboratory (USML-2) aboard the Space Shuttle Columbia, which flew from October 20 to November 5, 1995.

Source record↗

Modelling and Laboratory Testing of Particle Resuspension and Transport for the Assessment of Terrestrial-Borne Biological Contamination of the Samples on the Mars 2020 Mission

The Mars 2020 mission will land a rover on the surface of Mars that will acquire, encapsulate, and cache scientifically selected samples of martian material for possible return to Earth by a future mission. The samples will be individually encapsulated and sealed in sample tubes. Each sample, and therefore each sample tube, must be kept clean of viable organisms with a terrestrial origin, which may adhere to the rover on their own and/or on other non-biological particles. Therefore, contrary to previous missions to the Red Planet, Mars 2020 is subject to new and more stringent biological, organic and inorganic contamination requirements. This paper reports on the analyses and testing performed to assess the various vectors that can lead to the terrestrial-borne contamination of the samples, focusing on those that are predicted to be the larger contributors. Specifically, the contamination of the sample tubes is expected to be very small prior to the commencement of the mission’s science phase since these tubes are protected by so-called Fluid Mechanical Particle Barriers. Once on the surface of Mars however the sample tubes will be removed from their FMPBs and be subject to contamination from the rover. Of specific interest is the vector by which winds dislodge some particles from the surface of the rover and transport them to the surrounding soil. Naturally, such assessments require multi-disciplinary analyses involving at minimum the physics of particle adhesion and resuspension from surfaces, fluid mechanics and aerosols. Here we provide an overview of these models. We also report on particle resuspension experiments we have performed at the Jet Propulsion Laboratory to both guide and validate the aforementioned physics models.

Steltzner, Adam↗

Experimental Determination of Infrared Extinction Coefficients of Interplanetary Dust Particles

This technique is based on irradiating a single isolated charged dust particle suspended in balance by an electric field, and measuring the scattered radiation as a function of angle. The observed scattered intensity profile at a specific wavelength obtained for a dust particle of known composition is compared with Mie theory calculations, and the variable parameters relating to the particle size and complex refractive index are adjusted for a best fit between the two profiles. This leads to a simultaneous determination of the particle radius, the complex refractive index, and the scattering and extinction coefficients. The results of these experiments can be utilized to examine the IRAS and DIRBE (Diffuse Infrared Background Experiment) infrared data sets in order to determine the dust particle physical characteristics and distributions by using infrared models and inversion techniques. This technique may also be employed for investigation of the rotational bursting phenomena whereby large size cosmic and interplanetary particles are believed to fragment into smaller dust particles.

Spann, J. F., Jr.↗

Key and Driving Requirements for the Juno Payload of Instruments

The Juno Mission was selected in the summer of 2005 via NASA's New Frontiers competitive AO process (refer to http://www.nasa.gov/home/hqnews/2005/jun/HQ_05138_New_Frontiers_2.html). The Juno project is led by a Principle Investigator based at Southwest Research Institute [SwRI] in San Antonio, Texas, with project management based at the Jet Propulsion Laboratory [JPL] in Pasadena, California, while the Spacecraft design and Flight System Integration are under contract to Lockheed Martin Space Systems Company [LM-SSC] in Denver, Colorado. the payload suite consists of a large number of instruments covering a wide spectrum of experimentation. The science team includes a lead Co-investigator for each one of the following experiments: A Magnetometer experiment (consisting of both a FluxGate Magnetometer (FGM) built at Goddard Space Flight Center GSFC] and a Scalar Helium Magnetometer (SHM) built at JPL, a MicroWave Radiometer (MWR) also built at JPL, a Gravity Science experiment (GS) implemented via the telecom subsystem, two complementary particle instruments (Jovian Auroral Distribution Experiment, JADE developed by SwRI and Juno Energetic-particle Detector Instrument, JEDI from the Applied Physics Lab (APL)--JEDI and JADE both measure electrons and ions), an Ultraviolet Spectrometer (UVS) also developed at SwRI, and a radio and plasma (WAVES) experiment (from the University of Iowa). In addition, a visible camera (JunoCam) is included in the payload to facilitate education and public outreach (designed & fabricated by Malin Space Science Systems [MSSS]).

challenges↗

Ice Particle Impacts on a Flat Plate

An experimental study was conducted at the Ballistic Laboratory of NASA Glenn Research Center to study the impact of ice particles on a stationary flat surface target set at 45 degrees with respect to the direction of motion of the impinging particle (Figure 1). The experiment is part of NASA efforts to study the physics involved in engine power-loss events due to ice-crystal ingestion and ice accretion formation inside engines. These events can occur when aircraft encounter high-altitude convective weather.

ice particle↗

Physics and chemistry

The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) rheology of assemblies of inelastic, frictional particles; (2) grain dynamics in zero gravity; (3) properties of tenuous fractal aggregates; (4) orientation of weakly ferroelectric dust grains; (5) supersonic nozzle beam; and (6) some astrophysical cluster experiments. The required capabilities and desired hardware for the facility are detailed.

Moskovits, Martin↗

Interactive Soil Dust Aerosol Model in the GISS GCM: Sensitivity of the Soil Dust Cycle to Radiative Properties of Soil Dust Aerosols - Part 1

The sensitivity of the soil dust aerosol cycle to the radiative forcing by soil dust aerosols is studied. Four experiments with the NASA/GISS atmospheric general circulation model, which includes a soil dust aerosol model, are compared, all using a prescribed climatological sea surface temperature as lower boundary condition. In one experiment, dust is included as dynamic tracer only (without interacting with radiation), whereas dust interacts with radiation in the other simulations. Although the single scattering albedo of dust particles is prescribed to be globally uniform in the experiments with radiatively active dust, a different single scattering albedo is used in those experiments to estimate whether regional variations in dust optical properties, corresponding to variations in mineralogical composition among different source regions, are important for the soil dust cycle and the climate state. On a global scale, the radiative forcing by dust generally causes a reduction in the atmospheric dust load corresponding to a decreased dust source flux. That is, there is a negative feedback in the climate system due to the radiative effect of dust. The dust source flux and its changes were analyzed in more detail for the main dust source regions. This analysis shows that the reduction varies both with the season and with the single scattering albedo of the dust particles. By examining the correlation with the surface wind, it was found that the dust emission from the Saharan/Sahelian source region and from the Arabian peninsula, along with the sensitivity of the emission to the single scattering albedo of dust particles, are related to large scale circulation patterns, in particular to the trade winds during Northern Hemisphere winter and to the Indian monsoon circulation during summer. In the other regions, such relations to the large scale circulation were not found. There, the dependence of dust deflation to radiative forcing by dust particles is probably dominated by physical processes with short time scales. The experiments show that dust radiative forcing can lead to significant changes both in the soil dust cycle and in the climate state. To estimate dust concentration and radiative forcing by dust more accurately, dust size distributions and dust single scattering albedo in the model should be a function of the source region, because dust concentration and climate response to dust radiative forcing are sensitive to dust radiative parameters.

Perlwitz, Jan↗

Remote sensing of smoke, clouds, and radiation using AVIRIS during SCAR experiments

During the past two years, researchers from several institutes joined together to take part in two SCAR experiments. The SCAR-A (Sulfates, Clouds And Radiation - Atlantic) took place in the mid-Atlantic region of the United States in July, 1993. remote sensing data were acquired with the Airborne Visible Infrared Imaging Spectrometer (AVIRIS), the MODIS Airborne Simulator (MAS), and a RC-10 mapping camera from an ER-2 aircraft at 20 km. In situ measurements of aerosol and cloud microphysical properties were made with a variety of instruments equipped on the University of Washington's C-131A research aircraft. Ground based measurements of aerosol optical depths and particle size distributions were made using a network of sunphotometers. The main purpose of SCAR-A experiment was to study the optical, physical and chemical properties of sulfate aerosols and their interaction with clouds and radiation. Sulfate particles are believed to affect the energy balance of the earth by directly reflecting solar radiation back to space and by increasing the cloud albedo. The SCAR-C (Smoke, Clouds And Radiation - California) took place on the west coast areas during September - October of 1994. Sets of aircraft and ground-based instruments, similar to those used during SCAR-A, were used during SCAR-C. Remote sensing of fires and smoke from AVIRIS and MAS imagers on the ER-2 aircraft was combined with a complete in situ characterization of the aerosol and trace gases from the C-131A aircraft of the University of Washington and the Cesna aircraft from the U.S. Forest Service. The comprehensive data base acquired during SCAR-A and SCAR-C will contribute to a better understanding of the role of clouds and aerosols in global change studies. The data will also be used to develop satellite remote sensing algorithms from MODIS on the Earth Observing System.

Gao, Bo-Cai↗

Charged particle concepts for fog dispersion

Charged particle techniques hold promise for dispersing warm fog in the terminal area of commercial airports. This report focuses on features of the charged particle technique which require further study. The basic physical principles of the technique and the major verification experiments carried out in the past are described. The fundamentals of the nozzle operation are given. The nozzle characteristics and the theory of particle charging in the nozzle are discussed, including information from extensive literature on electrostatic precipitation relative to environmental pollution control and a description of some preliminary reported analyses on the jet characteristics and interaction with neighboring jets. The equation governing the transfer of water substances and of electrical charge is given together with a brief description of several semi-empirical, mathematical expressions necessary for the governing equations. The necessary ingredients of a field experiment to verify the system once a prototype is built are described.

Frost, W.↗

Study on 2012 March 7 Solar Particle Event and Forbush Decrease with the PAMELA Experiment

The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astro-physics) spaceborne experiment was launched on 15 June 2006 and has been continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 megaelectronvolts to several hundreds of gigaelectronvolts. The on-board instrumentation is built around a permanent magnet with a silicon microstrip tracker, providing charge and track detection information. During solar maximum conditions of solar cycle 24, PAMELA has been providing key information about solar energetic particles (SEPs) and their influence at Earth. We discuss here the recent 2012 March 7 SEP event with a brief comment on the subsequent Forbush decrease, registered by PAMELA. This event was also observed by Fermi/LAT (Large Area Telescope) exhibiting unprecedented time-extended gamma-ray emission (greater than 100 megaelectronvolts) lasting nearly 20 hours. We compare the derived accelerated ion population at the Sun with the ion population measured in space by PAMELA and discuss the implications for particle acceleration.

Forbush Decrease↗