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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 379 records · Page 21
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NASA NTRS1989

The proton temperature and the total hourly variance of the magnetic field components in different solar wind speed regions

A comparison has been made between the predictions of the theory for radial variations of both Alfvenic fluctuations and solar wind proton temperatures proposed by Tu (1987, 1988) and the statistical results of hourly averaged plasma and magnetic field data observed by Helios 1 and 2 from launch through 1980 for different solar wind speed regimes. The comparison shows that for speed ranges between 500-800 km/s, the radial variation of the proton temperature between 0.3 and 1 AU can be explained by heating from the cascade energy which is determined by the radial variation of the total variance of magnetic field vector.

Tu, Chuan-Yi↗
NASA NTRS1988

Data catalog series for space science and applications flight missions. Volume 5A: Descriptions of astronomy, astrophysics, and solar physics spacecraft and investigations. Volume 5B: Descriptions of data sets from astronomy, astrophysics, and solar physics spacecraft and investigations

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of data sets of astronomy, astrophysics, solar physics spacecraft and investigations. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Kim, Sang J.↗
NASA NTRS1988

Data Catalog Series for Space Science and Applications Flight Missions: Descriptions of Data Sets from Geostationary and High-Altitude Scientific Spacecraft and Investigations - Volume 2B

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of data sets from geostationary and high altitude scientific spacecraft and investigations. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Schofield, Norman J.↗
NASA NTRS1988

Data catalog series for space science and applications flight missions. Volume 1A: Descriptions of planetary and heliocentric spacecraft and investigations, second edition

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of planetary and heliocentric spacecraft and associated experiments. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also included.

Cameron, Winifred Sawtell↗
NASA NTRS1989

Data catalog series for space science and applications flight missions. Volume 6: Master index volume

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA, and other U.S. government agencies. This volume contains the Master Index. The following spacecraft are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Horowitz, Richard↗
NASA NTRS1989

Data catalog series for space science and applications flight missions. Volume 4B: Descriptions of data sets from meteorological and terrestrial applications spacecraft and investigations

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of data sets from meteorological and terrestrial applications spacecraft and investigations. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Ng, Carolyn↗
NASA NTRS1986

Data catalog series for space science and applications flight missions. Volume 3B: Descriptions of data sets from low- and medium-altitude scientific spacecraft and investigations

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of data sets from low and medium altitude scientific spacecraft and investigations. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Jackson, John E.↗
NASA NTRS1987

Data catalog series for space science and applications flight missions. Volume 1B: Descriptions of data sets from planetary and heliocentric spacecraft and investigations

The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of planetary and heliocentric spacecraft and associated experiments. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

Horowitz, Richard↗
NASA NTRS1990

Heliocentric distance and temporal dependence of the interplanetary density-magnetic field magnitude correlation

The Helios, IMP 8, ISEE 3, ad Voyager 2 spacecraft are used to examine the solar cycle and heliocentric distance dependence of the correlation between density n and magnetic field magnitude B in the solar wind. Previous work had suggested that this correlation becomes progressively more negative with heliocentric distance out to 9.5 AU. Here it is shown that this evolution is not a solar cycle effect, and that the correlations become even more strongly negative at heliocentric distance larger than 9.5 AU. There is considerable variability in the distributions of the correlations at a given heliocentric distance, but this is not simply related to the solar cycle. Examination of the evolution of correlations between density and speed suggest that most of the structures responsible for evolution in the anticorrelation between n and B are not slow-mode waves, but rather pressure balance structures. The latter consist of both coherent structures such as tangential discontinuities and the more generally pervasive 'pseudosound' which may include the coherent structures as a subset.

Roberts, D. A.↗
NASA NTRS1990

Large-scale variations of thermal electron parameters in the solar wind between 0.3 and 1 AU

Variations of thermal electron parameters in the solar wind are studied at heliocentric distances from 0.3 to 1 AU using Helios data from 1974 to spring 1976 just before solar minimum. Consideration is given to variations across plasma streams and across the sector structure of the IMF. It is found that, in high-speed streams in the interior of magnetic sectors, the electron temperatures are relatively low and strongly anisotropic. The electron temperatures become larger and less anisotropic toward sector boundaries in the slow solar wind. Radial gradients for the thermal electron parameters and polytrope indices for the core temperatures and electron temperatures are studied. Evidence is presented that the electrons in high-speed streams are heated by external heat sources. Interplanetary electrostatic potential differences caused by the thermal electron pressure gradients are estimated to be between 30 and 90 V.

Pilipp, W. G.↗
NASA NTRS1990

Transport and turbulence modeling of solar wind fluctuations

A detailed derivation of a transport model for MHD fluctuations in the solar wind is presented. Dynamical equations based on a two-length scale expansion are derived from which the evolution of various wavenumber spectra may be computed, including magnetic and kinetic energies, cross helicity, induced electric field, and the corresponding helicities. Several simple analytic solutions of the equations are consistent with Helios and Voyager predictions.

Zhou, YE↗
NASA NTRS1990

Acceleration of energetic particles by shock waves from large solar flares

Time-intensity profiles for solar proton events are analyzed with respect to the acceleration of energetic particles from the ambient solar wind by an interplanetary shock. The time-intensity profiles are derived from the Helio 1 particle data base for 1974 to 1984. It is found that many of the large proton events display a prolonged plateau. The Fe/O abundances in the large proton events are studied. It is observed that initially the Fe/O ratio is high (about 1.0), but after proton intensities increase to about 100 protons/sq cm sr sec MeV the Fe/O ratio decreases to a value near 0.1.

Reames, Donald V.↗
NASA NTRS1991

The solar cycle variation of the rates of CMEs and related activity

Coronal mass ejections (CMEs) are an important aspect of the physics of the corona and heliosphere. This paper presents results of a study of occurrence frequencies of CMEs and related activity tracers over more than a complete solar activity cycle. To properly estimate occurrence rates, observed CME rates must be corrected for instrument duty cycles, detection efficiencies away from the skyplane, mass detection thresholds, and geometrical considerations. These corrections are evaluated using CME data from 1976-1989 obtained with the Skylab, SMM and SOLWIND coronagraphs and the Helios-2 photometers. The major results are: (1) the occurrence rate of CMEs tends to track the activity cycle in both amplitude and phase; (2) the corrected rates from different instruments are reasonably consistent; and (3) over the long term, no one class of solar activity tracer is better correlated with CME rate than any other (with the possible exception of type II bursts).

Webb, David F.↗
NASA NTRS1992

New meteoroid model predictions for directional impacts on LDEF

An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (helios, Pioneer, Galileo, and Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space (Divine, 1992, in preparation). For a spacecraft in geocentric orbit, the effects of gravitational focusing and shielding by the Earth were derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on the Long Duration Exposure Facility (LDEF).

Divine, Neil↗
NASA NTRS1991

Filament disappearances and associated shocks of May 1979

In late May 1979 a shock was seen at each of two locations separated by about 90 deg in heliolongitude and at about the same time. A shock was detected near the earth, and a shock was detected at Helios 1 when it was off the sun's west limb. Some authors have considered that these shocks were part of the same event, which originated with a filament disappearance near 65 deg W. The paper discusses the observations which show that a large complex filament, extending from 20 deg to 70 deg W, disappeared in several places, probably generating more than one shock. The shock detected near earth was probably associated with a filament section which disappeared near the central meridian. If this is the case, then the interplanetary scintillation observations of this time period can be explained without invoking highly anisotropic shock propagation.

Cane, H. V.↗
NASA NTRS1991

MeV/n ions associated with corotating high-speed solar wind streams at less than 1 AU during 1978 to 1986

Data from the Goddard Space Flight Center experiments on the ISEE 3/ICE, IMP 8, and Helios 1 spacecraft are used to investigate ion enhancements of more than 1 MeV/n associated with corotating high-speed solar wind streams at least 1 AU during 1978-1986. The observations are consistent with ion acceleration from the solar wind by corotating shocks in the outer heliosphere.

Richardson, I. G.↗
NASA NTRS1993

New meteoroid model predictions for directional impacts on LDEF

An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (Helios, Pioneer, Galileo, Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space. For a spacecraft in geocentric orbit the effects of gravitational focussing and shielding by the Earth have been newly derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on LDEF.

Divine, Neil↗
NASA NTRS1992

A model for coronal streamer observations using the SOHO coronagraph instrumentation

The SOHO (Solar and Heliospheric Observatory) coronagraphs will offer an unprecedented opportunity to observe coronal streamer material and determine its outward motion. The inner C1 and C2 coronagraphs should enable ready identification of coronal streamers and their surface manifestations. The outer C3 coronagraph should be able to trace streamers to nearly interplanetary distances from the Sun. Using a modeling program designed to determine parameters from co-rotating heliospheric material viewed by the Helios spacecraft, the locations in position angle and distance from the Sun of several modeled streamers are shown. These models demonstrate the expected differences in streamer location when different assumptions are used for the outward acceleration of the streamer material.

Jackson, Bernard V.↗