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  • Chemistry  (11,378)
  • Polymer and Materials Science  (5,147)
  • SOLAR PHYSICS  (474)
  • 1975-1979  (12,831)
  • 1977  (6,387)
  • 1976  (6,444)
Collection
Keywords
Publisher
Years
  • 1975-1979  (12,831)
Year
  • 1
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    Solar and magnetospheric science (1976)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: The current status of the Solar Physics Program and the Magnetospheric Physics Program is discussed. The scientific context for each of the programs is presented, then the current programs and future plans are outlined.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-3440
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  • 2
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    ATM observations - X-ray results (1976)
    In:  Other Sources
    Details
    Publication Date: 2019-08-28
    Description: Preliminary results of the solar X-ray observations from Skylab are reviewed which indicate a highly structured nature for the corona, with closed magnetic-loop structures over a wide range of size scales. A description of the S-054 experiments is provided, and values are given for the parameters - including size, density, and temperature - describing a variety of typical coronal features. The structure and evolution of active regions, coronal holes, and bright points are discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysics and Space Science; 39; Jan. 197
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  • 3
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    An atlas of coronal hole boundary positions May 28 to November 21, 1973 (1976)
    In:  Other Sources
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    Publication Date: 2019-08-28
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 46; Feb. 197
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  • 4
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    Studies of the sun from Skylab (1977)
    In:  Other Sources
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    Publication Date: 2019-08-28
    Description: The new and exciting contributions to solar physics, which are resulting from the NASA Skylab Program, are reviewed and their broader implications in terms of solar cycle and solar-terrestrial relations are discussed. Among the 'active' phenomena studied by the Skylab Apollo Telescope Mount (ATM) solar experiments are coronal bright points, active regions, flares and coronal transient events. One of the most interesting quiet features studied by ATM has been coronal holes. The results of the first Skylab Solar Workshop, which was dedicated to a detailed investigation of these features and of their relationship with the solar wind, are also presented.
    Keywords: SOLAR PHYSICS
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  • 5
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    Extreme-ultraviolet observations of coronal holes. I - Locations, sizes and evolution of coronal holes, June 1973-January 1974 (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-08-27
    Description: The disk boundaries of coronal holes have been systematically determined from XUV observations taken during the manned Skylab missions (June 1973-January 1974). The resulting atlas was used to find the sizes, global distributions, differential rotation rates, growth/decay rates and lifetimes of holes during this period. The polar cap holes together covered 15% of the sun's total surface area, a number which remained surprisingly constant throughout Skylab despite the fact that each pole was independently evolving in time. Lower latitude holes contributed another 2 to 5%.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Mar. 197
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  • 6
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    Coronal holes as sources of solar wind (1976)
    In:  Other Sources
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    Publication Date: 2019-08-13
    Description: We investigate the association of high-speed solar wind with coronal holes during the Skylab mission by: (1) direct comparison of solar wind and coronal X-ray data; (2) comparison of near-equatorial coronal hole area with maximum solar wind velocity in the associated streams; and (3) examination of the correlation between solar and interplanetary magnetic polarities. We find that all large near-equatorial coronal holes seen during the Skylab period were associated with high-velocity solar wind streams observed at 1 AU.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 46; Feb. 197
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  • 7
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    Flare build-up study; Proceedings of the Workshop, Falmouth, Mass., September 8-11, 1975 (1976)
    In:  Other Sources
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    Publication Date: 2019-07-27
    Description: The papers deal with problems which might be common to solar flares and earth's magnetosphere, problems associated with the initial phases of the flare phenomenon, the acceleration processes that seem to occur in flares and the magnetosphere, as well as the buildup and storage of flare energy in magnetic-field structures. Topics include the active role of magnetic fields in providing flare energy, current-sheet models of solar flares, the role of plasma turbulence in flare development, similarities and differences between magnetospheric substorms and solar flares, observations of magnetic merging in earth's magnetotail during magnetospheric substorms, evidence for magnetic-energy storage in coronal active regions, the possible role of transition-zone instabilities in preflare energy buildup, and flare energy storage and deposition. Other papers discuss energy release through the interaction of coronal magnetic fields, photospheric electric currents as a source of flare energy, magnetic-energy buildup in the solar atmosphere, magnetic and velocity fields in an active region, flare onset at meter wavelengths, laboratory experiments on field-line reconnection, key problems in auroral flare processes, and the solar-physics Shuttle/Spacelab program. Individual items are announced in this issue.
    Keywords: SOLAR PHYSICS
    Type: Flare build-up study Workshop; Sept. 8-11, 1975; Falmouth, MA; US
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  • 8
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    Evolution pattern of the exploding granules (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Observational features of exploding granules that may be of some importance for the theory of unsteady convection are discussed on the basis of a time sequence of high-definition photographs of the solar granulation obtained during a Stratoscope flight. The evolutionary pattern of exploding granules is summarized schematically, and several characteristic features are derived from a study of seven such granules. The exploding-granule phenomenon is interpreted qualitatively in terms of cooling at the photospheric level and the subsequent sinking of cold matter at the center of a granule due to loss of buoyancy
    Keywords: SOLAR PHYSICS
    Type: Colloquium on Problems of stellar convection; Aug 16, 1976 - Aug 20, 1976; Nice; France
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  • 9
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    Results of correlative studies of a complex solar active region /McMath 12387/ during the Skylab mission (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Results of correlative studies employing Skylab/ATM X-Ray Telescope filter-heliograms, solar magnetograms, and H alpha spectroheliograms of the complex solar active region McMath 12387 for 10-18 June 1973 are presented. Evolutionary changes within the complex region are discussed. Magnetic field calculations, using both potential and force-free models, have been performed and the results are presented. We also determine temperatures, emission measures, and electron densities and show the variation with time of the X-ray emission from the entire complex.
    Keywords: SOLAR PHYSICS
    Type: Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs; May 29, 1975 - May 31, 1975|Open Meetings of Working Groups on Physical Sciences; May 29, 1975 - Jun 07, 1975; Varna; Bulgaria
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  • 10
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    The temperature and density structures of an X-ray flare during the decay phase (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The X-ray flare of 9 August 1973 was characterized by a spatially small kernel structure which persisted throughout its duration. The decay phase of this flare was observed in the objective grating mode of the X-ray telescope aboard the Skylab. Data analysis was carried out by scanning the images with a microdensitometer, converting the density arrays to energy using laboratory film calibration data and taking cross sections of the energy images. The 9 August flare shows two distinct periods in its decay phase, involving both cooling and material loss. The objective grating observations reveal that the two phenomena are separated in time. During the earlier phase of the flare decay, the distribution of emission measure as a function of temperature is changing, the high temperature component of the distribution being depleted relative to the cooler body of plasma. As the decay continues, the emission measure distribution stabilizes and the flux diminishes as the amount of material at X-ray emitting temperatures decreases.
    Keywords: SOLAR PHYSICS
    Type: Open Meetings of Working Groups on Physical Sciences; May 29, 1975 - Jun 07, 1975; Varna; Bulgaria|Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs; May 29, 1975 - May 31, 1975
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  • 11
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    The profile of the helium 584 A solar line - Preliminary results from rocket-borne resonance absorption spectrometer (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: A measurement of the line profile of the He I 584 A line from the sun has been made on board a rocket on 20 January 1975. Wavelength resolution is obtained by the resonance absorption method. The instrument is described, and its performance in flight is analysed. The principles of data reduction are given, and preliminary results are presented and compared with available data from other sources. The width of the solar He I resonance line is found to be larger than 110 mA.
    Keywords: SOLAR PHYSICS
    Type: Open Meetings of Working Groups on Physical Sciences; May 29, 1975 - Jun 07, 1975; Varna; Bulgaria|Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs; May 29, 1975 - May 31, 1975
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  • 12
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    Ultraviolet stellar spectra obtained with Skylab experiment S019 (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: SOLAR PHYSICS
    Type: AIAA PAPER 74-1244 , Conference on Scientific investigations on the Skylab satellite; Oct 30, 1974 - Nov 01, 1974; Huntsville, AL
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  • 13
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    The sun as a magnetic star (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The sun as a magnetic star is described on the basis of recent work on solar magnetism. Observations at an arbitrary angle to the rotation axis would show a 22-year polar field variation and a 25-day equatorial sector variation. The sector variation would be similar to an oblique rotator with an angle of 90 deg between the magnetic and rotational axis.
    Keywords: SOLAR PHYSICS
    Type: Colloquium on Physics of Ap-stars; Sep 08, 1975 - Sep 11, 1975; Vienna; Austria
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  • 14
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    Skylab experiment SO73: Gegenschein/zodiacal light (1976)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A 10 color photoelectric polarimeter was used to measure the surface brightness and polarization associated with zodiacal light, background starlight, and spacecraft corona during each of the Skylab missions. Fixed position and sky scanning observations were obtained during Skylab missions SL-2 and SL-3 at 10 wavelenghts between 4000A and 8200A. Initial results from the fixed-position data are presented on the spacecraft corona and on the polarized brightness of the zodiacal light. Included among the fixed position regions that were observed are the north celestial pole, south ecliptic pole, two regions near the north galactic pole, and 90 deg from the sun in the ecliptic. The polarized brightness of the zodiacal light was found to have the color of the sun at each of these positions. Because previous observations found the total brightness to have the color of the sun from the near ultraviolet out to 2.4 micrometers, the degree of polarization of the zodiacal light is independent of wavelength from 4000A to 8200A.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-150186
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  • 15
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    Time development of a small solar X-ray burst (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The 5.1-7.2 A X-ray emission from the sun was studied via OSO-8 with a high-resolution PET crystal spectrometer during the week of 17 November 1975, when the sun was active. The combination of good temporal and spectral resolution permitted the analysis of the data with multithermal coronal models over the course of a small X-ray burst.
    Keywords: SOLAR PHYSICS
    Type: COSPAR, Plenary Meeting; Jun 08, 1976 - Jun 19, 1976; Philadelphia, PA
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  • 16
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    Modeling of the orbital evolution of vaporizing dust particles near the sun (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: SOLAR PHYSICS
    Type: Interplanetary dust and zodiacal light; Jun 10, 1975 - Jun 13, 1975; Heidelberg
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  • 17
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    EUV flux variations with solar rotation observed during 1974-1976 from AE satellites C, D, and E (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Solar EUV fluxes in the spectral range from 140 to 1850 A have been observed by spectrophotometers on the satellites AE-C, D, and E. Variations over the long period of one or two years cannot be verified quantitatively, as the observed small variations are of the same magnitude as possible variations of instrumental sensitivities and estimated uncertainties of absolute values from the rocket experiment which established the calibration of the AE-C instrument. Fortunately, no similar difficulty exists for the interpretation of observed EUV variations within smaller time periods up to that of a full solar rotation. Results from AE-C observations for many different wavelength groups for the year 1974 are shown by some detail and compared with some recent observations made by the AE-D and AE-E instruments.
    Keywords: SOLAR PHYSICS
    Type: COSPAR, Plenary Meeting; Jun 08, 1976 - Jun 19, 1976; Philadelphia, PA
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  • 18
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    High-precision infrared sky survey at wavelength 2.7 microns (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Preliminary results of an infrared survey of the equatorial sky zone (declinations 10 S to 10 N) with U.S. Air Force satellite sensors show that positions of previously unknown infrared sources are measured with an rms accuracy of 4 arc seconds, which is six times better than the best previous infrared survey. The search area per source for further study is thus 36 times smaller, so that identification of the infrared sources with optical objects in catalogs and sky photographs is facilitated, as is reacquisition of the sources with ground-based infrared telescopes. The survey extends the content of near-infrared source catalogs to lower flux densities and adds information at a wavelength not observable from the ground. Objects found in the survey include cool giants and supergiants, long-period and semi-regular variable stars, and sources identified with faint red stars visible on the Palomar Observatory Sky Survey.
    Keywords: SOLAR PHYSICS
    Type: Modern utilization of infrared technology III: Civilian and military; Third Seminar; Aug 25, 1977 - Aug 26, 1977; San Diego, CA
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  • 19
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    Solar energetic particles below 10 MeV (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The information on solar acceleration and coronal propagation contained in low energy solar particle observations must be extracted from the effects of propagation in a dynamic interplanetary medium and the proximity of the earth's magnetosphere. The resulting separation reveals long-lived coronal injection and strong spatial ordering of coronal propagation.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 20
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    Evolution of the X-ray emitting corona preceding and after major solar events (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Soft X-ray emission from the sun during STIP Interval II, observed with the Lockheed Mapping X-ray Heliometer on the NASA OSO-8 satellite, is presented. In examining the emission versus time for extended intervals around the times of the Class 1B flare on March 28, 1976, and the Class 1B flare on April 30, 1976, we find significantly more low level flare activity prior to the major flares than after. Twelve modest X-ray bursts are investigated and no compelling case of a preflare brightening phase is observed. Preliminary correlations with the time history of emitted solar particles are discussed.
    Keywords: SOLAR PHYSICS
    Type: Plenary Meeting; Jun 07, 1977 - Jun 18, 1977; Tel Aviv; Israel
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  • 21
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    Mass ejections from the solar corona into interplanetary space (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Results obtained from analysis of Skylab coronagraph images of mass ejections from the solar corona are reviewed which demonstrate the importance of mass-ejection coronal transients to the interplanetary medium and which support the belief that magnetic forces are the primary mechanism driving mass ejections from the corona. Observations of 13 large ejection events are examined which indicate that coronal mass ejections contribute a nonnegligible fraction of the mass flux from the sun, especially toward the heliographic equator near the maximum of a solar activity cycle. It is shown that observed loop-shaped transients were associated with regions of increased magnetic field and with separations of unipolar field regions, that the forces driving the transients outward acted to great heights long after the onsets of the events, and that the behavior of the ejecta was magnetically controlled. It is concluded that mass ejections from the corona contributed at least 3% of the mass flux from the sun during the Skylab era and that the most common loop-shaped ejections are magnetically driven through the corona.
    Keywords: SOLAR PHYSICS
    Type: Plenary Meeting; Jun 07, 1977 - Jun 18, 1977; Tel Aviv; Israel
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  • 22
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    Solar particle emission (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: A variety of flare-associated and recurrent solar particle events are analyzed using the technique of 'mapping' the fluxes back to the estimated high coronal longitude of the interplanetary field line passing through the spacecraft. Often it is possible to separate temporal from spatial effects as well as those of coronal and interplanetary propagation. Considerable regularity appears in the coronal injection profiles deduced during events in 1969, 1972 and 1973, implying extended acceleration of protons about 0.3-7.5 MeV, helium and medium nuclei about 1 MeV/nuc and relativistic electrons. Clear associations are found in 1973 among energetic particle injection profiles, solar wind stream sources, and low coronal magnetic structure.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 23
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    Solar cycle review /General aspects/ (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Several topics are discussed in this review of the solar cycle. The basic solar-interplanetary magnetic structure is considered, and the high speed solar wind streams and their sunspot cycle variation are described, with attention to the sunspot cycle variation, the high speed solar wind streams and geomagnetic disturbances, and the causes of changes of the north-south component of the interplanetary magnetic field. Solar storms, solar flares, and magnetic bubbles are examined with attention directed to the solar cycle variation of transient polar activities and the interplanetary disturbances associated with solar storms. Some features of cosmic rays, the 11-year cycle variation and the Forbush decreases, are considered. Attention is also directed to the terrestrial atmosphere and to the outer planets and their relation to the solar cycle.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 24
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    Latitudinal variations in the solar wind (1976)
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    Publication Date: 2019-07-13
    Description: There are two classes of latitudinal solar wind variations - those which are an imprint of coronal processes, and those which are internally generated within the solar wind. An axisymmetric description of the latitudinal variations is presented. As an example, a large polar coronal hole is discussed, with attention to directed meridional flow in the corona out to five solar radii, temperature and density characteristics in a coronal hole and beyond, temperature effects in the interplanetary medium, internally generated meridional flow in the interplanetary medium, and the detection of polar hole material in the ecliptic at 1 AU.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 25
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    The internal plasma state of the high speed solar wind at 1 AU (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The character of particle velocity distributions in the high speed solar wind is described. It is found that electron distribution shapes differ from simple bi-Maxwellians in that a hot strongly beamed high energy electron component is always present, and is observed to move relative to a distinct low energy electron component along the magnetic field direction away from the sun. The velocity difference between hot and cold electron components appears, at times, to be strongly correlated with the local Alfven speed. Proton velocity distributions are also best represented by two relatively convecting unresolved components. Evidence is presented which supports the idea that the two-component proton structure observed in high speed regions is intimately related to fine scale velocity variations at 1 AU, and probably to prominent spatial and/or temporal structures present throughout that part of the corona from which the solar wind evolves.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 26
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    The physical properties of coronal holes (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Coronal hole data obtained by Skylab during the period May 1973 to February 1974 are reviewed for the region from the photosphere out through the low corona. Coronal holes have a significantly lower density and temperature than the typical background corona, possess an open divergent magnetic field structure, and are the source of the high-speed solar wind stream which give rise to recurrent geomagnetic storms. The photospheric, chromospheric, and coronal signatures of coronal holes are described, and the evolution of coronal holes is examined, with attention to the lifetimes, the differential rotation, and the areas covered by the holes. The association of coronal holes to large-scale magnetic fields and to disk activity is considered.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 27
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    Application of an axisymmetric implicit blunt body procedure - Computation of solar wind flows past terrestrial planets (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: A recently developed axisymmetric implicit unsteady Euler equation solver has been applied to the calculation of solar wind flows past terrestrial planets. The primary emphasis of this paper is on the application of that computational technique to the calculation of the flow field properties of steady, axisymmetric, supersonic/hypersonic flows past blunt-nosed shapes characteristic of interplanetary solar wind flows past both magnetic and nonmagnetic planets. The purpose is to demonstrate both the accuracy and flexibility of this new technique as well as to present a novel application of such supersonic blunt-body procedures.
    Keywords: SOLAR PHYSICS
    Type: AIAA PAPER 77-700 , Conference on Fluid and Plasmadynamics; Jun 27, 1977 - Jun 29, 1977; Albuquerque, NM
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  • 28
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    Solar wind H-3 and C-14 abundances and solar surface processes (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Tritium is measured as a function of depth in a Surveyor 3 sample. The upper limit for solar-wind-implanted tritium gives an H-3/H-1 limit for the solar wind of 10 to the -11th power. The temperature-release patterns of C-14 from lunar soils are measured. The C-14 release pattern from surface soils differs from a trench-bottom soil and gives positive evidence for the presence of C-14 in the solar wind with a C-14/H-1 ratio of approximately 6 by 10 to the -11th power. This C-14 content fixes a minimal magnitude for nuclear processes on the solar surface averaged over the past 10,000 yr. The H-3 and C-14 contents combine to require that either the mixing rate above the photosphere be rapid or that the H-3 produced by nuclear reactions be destroyed by secondary nuclear reactions before escaping in the solar wind.
    Keywords: SOLAR PHYSICS
    Type: Lunar Science Conference; Mar 15, 1976 - Mar 19, 1976; Houston, TX
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  • 29
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    Preliminary results from the S-056 X-ray telescope experiment aboard the Skylab-Apollo Telescope Mount (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: SOLAR PHYSICS
    Type: AIAA PAPER 74-1233 , Conference on Scientific investigations on the Skylab satellite; Oct 30, 1974 - Nov 01, 1974; Huntsville, AL
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  • 30
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    The calculation of theoretical chromospheric models and predicted OSO I spectra (1977)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: A computer program was developed which, given a line list and a model atmosphere, computes a solar ultraviolet spectrum, broadens it, plots it together with an observed spectrum, and labels each line. An iterative procedure is utilized. Several of the computed and observed spectra are presented.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-149816 , SAR-3
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  • 31
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    Wave-particle interaction phenomena associated with shocks in the solar wind (1977)
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    Publication Date: 2019-07-13
    Description: Microscopic wave-particle interaction phenomena must generally affect the evolution of a traveling interplanetary discontinuity such as a collisionless shock, and solar wind plasma instabilities should also be associated with interplanetary acceleration, diffusion, and dissipation. Recent local measurements from diagnostics on widely separated spacecraft illustrate some examples of these interaction phenomena, and two bounding cases are considered in detail here. It is shown that the interplanetary shock of September 14, 1974 (detected on IMP-7, 8, Hawkeye-1, and Pioneer 11) was associated with intense local electrostatic noise and ion acceleration, while the shock of January 6, 1975 (detected on IMP-7 and Helios-1) had no detectable electrostatic turbulence.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 32
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    Dynamic modeling of coronal and interplanetary responses to solar events (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Recent progress in the dynamic modeling of responses of the corona and interplanetary medium to solar events (such as surges, eruptive prominences, flares, etc.) is reviewed. In particular, coronal transients and wave phenomena are discussed in some detail including pertinent mathematical requirements. Within the context of hydrodynamics and magnetohydrodynamics, a summary of both one- and two-dimensional time-dependent models is presented. A comparison of theoretical results with ground-based optical, radio, ATM Skylab observations, Pioneer 9 and Pioneer 10 solar wind observations is also presented. It is illustrated that: (1) substantial progress has been made in the theoretical (i.e., numerical) modeling of coronal and interplanetary responses within the last few years; (2) two-dimensional, time-dependent modeling is needed to examine the details of nonlinear wave coupling; and (3) theoretical results of modeling appear to reproduce physical consequences successfully.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 33
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    68815 revisited (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Remeasurement of the particle track density as a function of depth in lunar breccia 68815 has yielded galactic cosmic-ray track densities consistent with a 2 m.y. surface exposure, in good agreement with results by other authors. The empirical track-production spectrum of Walker and Yuhas (1973) is confirmed. The solar-flare track profile is typical and shows no evidence of large-scale chipping. Radionuclide profiles (Mn-53) investigated by the Arnold group should thus be undisturbed and should provide a test of the Reedy-Arnold model and of the constancy of solar and galactic cosmic rays.
    Keywords: SOLAR PHYSICS
    Type: Lunar Science Conference; Mar 14, 1977 - Mar 18, 1977; Houston, TX
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  • 34
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    Solar proton fluxes since 1956 (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The fluxes of protons emitted during solar flares since 1956 were evaluated. The depth-versus-activity profiles of Co-56 in several lunar rocks are consistent with the solar proton fluxes detected by experiments on several satellites. Only about 20% of the solar-proton-induced activities of Na-22 and Fe-55 in lunar rocks from early Apollo missions were produced by protons emitted from the sun during solar cycle 20 (1965-1975). The depth-versus-activity data for these radionuclides in several lunar rocks were used to determine the fluxes of protons during solar cycle 19 (1954-1964). The average proton fluxes for cycle 19 are about five times those for both the last million years and for cycle 20 and are about five times the previous estimate for cycle 19 based on neutron-monitor and radio ionospheric measurements. These solar-proton flux variations correlate with changes in sunspot activity.
    Keywords: SOLAR PHYSICS
    Type: Lunar Science Conference; Mar 14, 1977 - Mar 18, 1977; Houston, TX
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  • 35
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    Observations of solar active regions and solar flares by OSO-7 (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Contributions made to the physics of coronal active regions and flares by the extreme ultraviolet and soft X-ray spectroheliograph on OSO-7 were discussed. Coronal structures above active regions were discussed from the point of view of their morphology and physical properties, including their relationship to photospheric and coronal magnetic fields. OSO-7 also recorded flares with sufficient spatial and temporal resolution to record, in some instances for the first time, the extreme ultraviolet and soft X-ray emission associated with such chromospheric phenomena as filament activation and the emergence of satellite sunspots. Flare phenomena were reviewed in terms of the several stages of evolution typically associated with the event.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-78043 , OSO Workshop; Nov 08, 1977; Boulder, CO; United States
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  • 36
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    The Lyman alpha coronagraph (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The rocket-borne Lyman alpha coronagraph (RLAC) is to be used in the absence of a natural solar eclipse to determine coronal temperatures from measurements of the line width of Lyman-alpha and to determine neutral hydrogen densities of coronal material from the absolute intensity. The coronagraph consists of a 75-cm Fastie-Ebert scanning spectrometer with an AMR 641 photoelectric detection system, an off-axis parabolic primary mirror, and an occulting system. A special optical arrangement achieves rejection of radiation from the solar disk.
    Keywords: SOLAR PHYSICS
    Type: Plenary Meeting; Jun 07, 1977 - Jun 18, 1977; Tel Aviv; Israel
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  • 37
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    Skylab observations of X-ray loops connecting separate active regions (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: One hundred loops interconnecting 94 separate active solar regions detectable in soft X-rays were identified during the Skylab mission. While close active regions are commonly interconnected with loops, the number of such interconnections decreases steeply for longer distances; the longest interconnecting loop observed in the Skylab data connected regions separated by 37 deg. Several arguments are presented which support the point of view that this is the actual limit of the size of magnetic interconnections between active regions. No sympathetic flares could be found in the interconnected regions. These results cast doubt on the hypothesis that accelerated particles can be guided in interconnecting loops from one active region to another over distances of 100 deg or more and eventually produce sympathetic flares in them.
    Keywords: SOLAR PHYSICS
    Type: Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs; May 29, 1975 - May 31, 1975|Open Meetings of Working Groups on Physical Sciences; May 29, 1975 - Jun 07, 1975; Varna; Bulgaria
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  • 38
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    Solar wind and energetic particle events of 20-30 June 1974 analyzed using measurements of interplanetary radio scintillations at 34.3 MHz (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Keywords: SOLAR PHYSICS
    Type: Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs; May 29, 1975 - May 31, 1975|Open Meetings of Working Groups on Physical Sciences; May 29, 1975 - Jun 07, 1975; Varna; Bulgaria
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  • 39
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    Multicolor photometry of low-light-level phenomena from Skylab (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A brief description is given of the instrument and observing routines, together with a listing of observations from Skylab and of coordinated observations from Pioneers 10 and 11 and from the ground. Initial results are presented on the spacecraft corona and on the distribution of brightness and polarization at 7100 A over the antisolar hemisphere.
    Keywords: SOLAR PHYSICS
    Type: AIAA PAPER 74-1249 , Conference on Scientific investigations on the Skylab satellite; Oct 30, 1974 - Nov 01, 1974; Huntsville, AL
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  • 40
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    Initial results from the EUV spectroheliometer on ATM (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The Harvard College Observatory photoelectric spectroheliometer on the Apollo Telescope Mount operated correctly in orbit from May 29, 1973 to February 7, 1974. During this period, many thousands of spatial and spectral scans at extreme ultraviolet wavelengths were recorded during observations of a variety of solar features. The construction and modes of operation of the instrument are outlined, and the principal scientific results from a preliminary analysis of the data are described.
    Keywords: SOLAR PHYSICS
    Type: AIAA PAPER 74-1230 , Conference on Scientific investigations on the Skylab satellite; Oct 30, 1974 - Nov 01, 1974; Huntsville, AL
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  • 41
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    Pioneer 10, 11 observations of evolving solar wind streams and shocks beyond 1 AU (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Observations between 1 and 5 AU by Pioneers 10 and 11 have led to the identification of large numbers of interplanetary shocks. Both forward and reverse shocks, which begin to develop beyond 1.5 AU and which frequently appear as shock pairs, are found to accompany solar wind streams. The number of forward shocks continues to increase out to at least 5 AU. Reverse shocks are seen less often than forward shocks and, in some instances, disappear at larger distances. There is evidence that the shocks are corotating in the solar frame, as anticipated theoretically. The evolution of solar wind streams beyond 1 AU is profoundly affected by the shocks. A thick interaction region, with large enhancements in density, temperature, field strength and fluctuation level, forms in the region originally characterized by a positive velocity gradient. The solar wind and magnetic field properties adjacent to, and within, the interaction regions have been studied to determine their qualitative behavior and characteristic changes with distance. Several interplanetary shocks generated by solar flares have also been identified and analyzed.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 42
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    Mass ejections from the solar corona into interplanetary space (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Data are presented that show that during the Skylab era, mass ejections from the solar corona probably contributed at least 3% of the mass flux from the sun. The frequency of the transients is expected to increase with overall activity in the solar cycle, so more than 10% of the sun's mass efflux will be in the form of ejections at solar cycle maximum.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 43
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    Measurements of the solar wind using spacecraft radio scattering observations (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: This paper reviews radio scattering measurements of the solar wind carried out with coherent, monochromatic, and point-source spacecraft signals. The observed phenomena which include spectral and angular broadening, and phase as well as intensity scintillations, have provided measurements of the solar wind previously not available from radio astronomical observations. These cover a wide range of heliocentric distances (as close as 1.7 solar radii), and large- as well as small-scale electron density fluctuations.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 44
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    Energetic solar flare particles and interplanetary shock waves (1977)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Estimates from hard X-ray measurements show that for many flares the bulk of the flare energy is released in the form of approximately 10-100-keV energy electrons. The interaction of these electrons with the solar atmosphere can produce the optical, UV, EUV, and radio emissions observed during the flare impulsive phase. In addition, explosive heating and evaporation of the chromosphere by these electrons can produce the roughly 10 million K soft X-ray plasma. For the large solar flares which produce interplanetary shock waves, the accelerated approximately 10-100-keV electron population may produce the heating and mass motion required for mass ejection and the formation of the shock wave. The shock wave can in turn accelerate ions and electrons to higher energy as it travels through the corona and interplanetary medium.
    Keywords: SOLAR PHYSICS
    Type: L. D. de Feiter Memorial Symposium; Jun 07, 1977 - Jun 10, 1977; Tel Aviv; Israel
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  • 45
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    Computational techniques for solar wind flows past terrestrial planets: Theory and computer programs (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The interaction of the solar wind with terrestrial planets can be predicted using a computer program based on a single fluid, steady, dissipationless, magnetohydrodynamic model to calculate the axisymmetric, supersonic, super-Alfvenic solar wind flow past both magnetic and nonmagnetic planets. The actual calculations are implemented by an assemblage of computer codes organized into one program. These include finite difference codes which determine the gas-dynamic solution, together with a variety of special purpose output codes for determining and automatically plotting both flow field and magnetic field results. Comparisons are made with previous results, and results are presented for a number of solar wind flows. The computational programs developed are documented and are presented in a general user's manual which is included.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-2924 , NEAR-TR-140
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  • 46
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    Development of solar active regions (1976)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The birth, growth, and decay of solar active regions are described. The appearance of active regions in different atmospheric layers is examined, and the coronal extension of active regions is considered. The use of Skylab soft X-ray and extreme UV observations for studying the complex loop structure of active regions in the solar corona and the sensitive reactions of the upper atmospheric layers to newly emerging flux is explained. It was found that well developed active regions are much bigger in the corona than in the underlying sunspot groups and plages, and that many of the active regions are connected with others through systems of magnetic field lines, occasionally visible in soft X-rays. These interconnections, which may survive several solar rotations, indicate bigger complexes on the sun than one individual active region.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 47
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    The sun since the Bronze Age (1976)
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    Publication Date: 2019-07-13
    Description: An investigation is conducted concerning the behavior of the sun during the last 7000 years. The C-14 content in carbonaceous fossil material can be used as an indicator regarding the level of solar activity at the time when the carbon was assimilated in the process of photosynthesis. Living trees, such as the bristlecone pine, provide a solar activity record to about 3000 B.C. The record can be extended with the aid of well-preserved dead wood to beyond 5000 B.C. The results of an analysis of solar activity levels as a function of time on the basis of C-14 contents are presented in a graph. Attention is given to the Maunder Minimum, a history of the sun in the last 5000 years, an interpretation of the major C-14 excursions, and the sun and climate history.
    Keywords: SOLAR PHYSICS
    Type: International Symposium on Solar-Terrestrial Physics; Jun 07, 1976 - Jun 18, 1976; Boulder, CO
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  • 48
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    Proceedings of the Symposium on the Study of the Sun and Interplanetary Medium in Three Dimensions (1976)
    In:  CASI
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    Publication Date: 2019-07-13
    Description: A series of papers are presented from a symposium attended by over 200 European and American scientists to examine the importance of exploring the interplanetary medium and the sun by out-of-the-ecliptic space missions. The likely scientific returns of these missions in the areas of solar, interplanetary, and cosmic ray physics is examined. Theoretical models of the solar wind and its interaction with interplanetary magnetic fields are given.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-71097 , X-660-76-53 , May 15, 1975 - May 16, 1975; Greenbelt, MD; United States
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  • 49
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    The effect of the magnetic field on coronal transients (1977)
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    Publication Date: 2019-06-28
    Keywords: SOLAR PHYSICS
    Type: AFGL Contrib. Papers to the Study of Travelling Interplanetary Phenomena(1977; p 23-34
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  • 50
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    Bright X-ray arcs and the emergence of solar magnetic flux (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The Skylab S-056 and S-082A experiments and ground-based magnetograms have been used to study the role of bright X-ray arcs and the emergence of solar magnetic flux in the McMath region 12476. The S-056 X-ray images show a system of one or sometimes two bright arcs within a diffuse emitting region. The arcs seem to directly connect regions of opposite magnetic polarity in the photosphere. Magnetograms suggest the possible emergence of a magnetic flux. The width of the main arc is approximately 6 arcsec when most clearly defined, and the length is approximately 30-50 arcsec. Although the arc system is observed to vary in brightness over a period exceeding 24 hours, it remains fixed in orientation. The temperature of the main arc is approximately 3 x 10 to the 6th K. It is suggested that merging magnetic fields may provide the primary energy source, perhaps accompanied by resistive heating from a force-free current.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 216
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  • 51
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    H-alpha macrospicules - Identification with EUV macrospicules and with flares in X-ray bright points (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper presents observational evidence that two newly observed transient solar phenomena, EUV macrospicules and X-ray bright-point flares, are closely related. Time-lapse H-alpha filtergram observations of the limb in quiet regions show small surgelike eruptions called H-alpha macrospicules. From the similarity of H-alpha macrospicules and EUV macrospicules, and from comparison of simultaneous H-alpha and He II 304 A observations, we conclude that H-alpha macrospicules are EUV macrospicules viewed in H-alpha, although most EUV macrospicules are too faint in H-alpha to appear on H-alpha filtergrams of normal exposure. From comparison of simultaneous X-ray and H-alpha observations of flares in X-ray bright points situated on the limb, we show that flares in X-ray bright points often produce H-alpha macrospicules.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 218
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  • 52
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    Evolution of open magnetic structures on the sun - The Skylab period (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: High-resolution harmonic analysis of the measured photospheric magnetic field of the sun is used to construct models of open magnetic structures over a period of 11 solar rotations. The models successfully reproduce the surface location and topology of all coronal holes during the Skylab period. In addition, there is persistent evidence in the models that open field lines are associated with active regions in a systematic way. These associations are listed for the period studied; they suggest that open field lines are a basic feature of solar magnetism. Specific examples of the evolution of coronal holes and of calculated open structures are presented. Quantitative study of the measured field strength within and neighboring a hole confirms the fact that coronal hole regions are indistinguishable by local magnetic properties. However, the calculated field strengths at the footpoints of open field lines within coronal holes show distinct evolutionary patterns and may indicate that, at least in young coronal holes, a significant amount of magnetic flux is closed. Problems of studying magnetic field divergence by using these models are discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 218
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  • 53
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    Noncompressive density enhancements in the solar wind (1977)
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    Publication Date: 2019-06-27
    Description: When the bulk flow speed is nearly constant or falling, high densities are sometimes observed in the solar wind. These densities do not appear to be generated in interplanetary space. It is noted that the magnetic field is not enhanced within these events, and that the proton and/or electron temperatures are low, varying in opposition to the density. About 1/3 of these density events contains interplanetary magnetic field reversals, some of which are noisy and do not qualify as sector boundaries. It is estimated that the average event contains approximately 10 to the 16th g of material and 2.6 x 10 to the 31st ergs, so that aggregated events, when they are common, make a negligible contribution to the total mass and energy budget of the solar wind at 1 AU. It is suggested that there may be an association between density enhancements and solar coronal mass ejection events.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 82; Nov. 1
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  • 54
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    A self-consistent model of a thermally balanced quiescent prominence in magnetostatic equilibrium in a uniform gravitational field (1977)
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 53; Aug. 197
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  • 55
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    Mass and energy flow in the solar chromosphere and corona (1977)
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    Publication Date: 2019-06-27
    Description: The work reviews some investigations into the mass and energy flow in the solar chromosphere and corona; the objective of these investigations is the development of a physical model that will not only account for the physical conditions in the outer atmosphere of the sun, but can also be applied to the study of the outer atmospheres of other stars. Particular attention is given to mass and energy flow in regions with weak and strong magnetic fields, to observational evidence for wave heating and systematic mass flows, and to heating mechanisms. Consideration is given throughout to mechanisms of energy input and energy loss.
    Keywords: SOLAR PHYSICS
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  • 56
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    A survey on initial results of the Helios plasma experiment (1977)
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    Publication Date: 2019-06-27
    Description: The reported results are mainly based on data obtained during the first part of the Helios-1 mission. The sun was very quiet during the considered period. The data are, therefore, representative for comparatively stationary conditions in the solar corona. Data obtained concerning the protons were evaluated by means of a special computer routine. The significance of the data is discussed, taking into account the status of the corona and the interplanetary plasma during the considered part of the Helios-1 mission, fast stream structures in the region between 0.3 and 1 AU, radial gradients of fast and slow solar wind, and the separation of proton double streams and alpha-particles. Attention is also given to the 'strahl' in the electron distribution, differences between fast streams and slow plasma on the basis of the observed electron distributions, and radial gradients in the case of solar wind electron parameters.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysics - Zeitschrift fuer Geophysik; 42; 6, 19; 1977
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  • 57
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    The radial gradients and collisional properties of solar wind electrons (1977)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The plasma instrument on Mariner 10 carried out measurements of electron density and temperature in the interplanetary medium between heliocentric distances of 0.85 and 0.45 AU. Due to the stable coronal configuration and low solar activity during the period of observation, the radial variations of these quantities could be obtained. The power-law exponent of the core temperature was measured to be -0.3 + or - 0.04, and the halo temperature was found to be almost independent of heliocentric distance. The exponent of the power law for the density variation was 2.5 + or - 0.2 and the extrapolated value at 1 AU was consistent with measured values during the same period. Calculations of the core electron self-collision time, and the core-halo equipartition time were made as a function of radial distance. These measurements indicate a macroscale picture of a Coulomb-collisional core and a collisionless isothermal halo. Extrapolating back to the sun, core and halo temperatures become equal at a radial distance of approx. 2-15 radii.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-78026
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  • 58
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    Research in Solar Physics: Analysis of Skylab/ATM S-056 X-Ray Data (1977)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Data obtained by the X-ray event analyzer are described as well as methods used for film calibration. Topics discussed include analyses of the 15 June 1973 flare, oscillations in the solar soft X-ray flux, and deconvolution of X-ray images of the 5 September 1973 flare.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-150470 , ESD-MSFC-2145
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  • 59
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    High-temperature flare lines in the solar spectrum 171 A-630 A (1976)
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 205; Apr. 1
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  • 60
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    Solar-wind tritium limit and the mixing rate of the solar atmosphere (1976)
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    Publication Date: 2019-06-27
    Description: Tritium has been measured, in Surveyor 3 samples, some of which were adjacent to those in which solar-wind-implanted He-4 had previously been measured. Little of the H-3 can be attributed to solar-wind implantation. The upper limit for the H-3/He-4 ratio in the solar wind is four times ten to the minus tenth power and corresponds to a H-3/H-1 limit of two times ten to the minus eleventh power. This limit imposes a requirement on the mixing rate in the solar atmosphere if the H-3 production rate in solar-surface nuclear reactions is greater than 160 sq cm/sec.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 205; Apr. 1
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  • 61
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    A.t.m. observations on the X u.v. emission from solar flares (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper summarizes observations of selected solar flares made with a far-UV spectroheliograph (190-465 A) and a UV spectrograph (900-1900 A) aboard Skylab. The emission lines used in the present analysis are identified, and three events are described in detail: the flare of June 15, 1973, a small subflare observed on August 9, 1973, and the flare of January 21, 1974. Ultraviolet images of two other events are also presented in an attempt to sketch a general picture of a flare as seen in this spectral region. It is found that a small kernel seems to be the source of the primary energy release of a flare. The size, electron density, and ion temperature of a typical kernel are estimated, and it is noted that hot clouds of coronal gas at 20 million K surrounded the observed kernels. It is speculated that flare kernels might be very thin channels through which high-energy particles, originating in deep layers, are ejected into the corona.
    Keywords: SOLAR PHYSICS
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  • 62
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    Depletion of solar wind plasma near a planetary boundary (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A mathematical model is presented that describes the squeezing of solar wind plasma out along interplanetary magnetic field lines in the region between the bow shock and the effective planetary boundary (in the case of the earth, the magnetopause). In the absence of local magnetic merging the squeezing process should create a 'depletion layer', a region of very low plasma density just outside the magnetopause. Numerical solutions are obtained for the dimensionless magnetohydrodynamic equations describing this depletion process for the case where the solar wind magnetic field is perpendicular to the solar wind flow direction. For the case of the earth, the theory predicts that the density should be reduced by a factor exceeding 2 in a layer about 700-1300 km thick if the Alfven Mach number in the solar wind, is equal to 8. Scaling of the model calculations to Venus and Mars suggests layer thicknesses about 1/10 and 1/15 those of the earth, respectively, neglecting diffusion and ionospheric effects.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Apr. 1
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  • 63
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    Radial variation of solar-wind parameters (1976)
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    Publication Date: 2019-06-27
    Description: It is demonstrated that since fluctuations in the solar wind are not small, they can have important effects on the observed average values of parameters in the solar wind and their radial variation. The effect is distinct from the dynamical effect of waves and turbulence, and results from the averaging process. It is concluded that, for example, the average density of the solar wind need not vary as the inverse square of distance, even if the average velocity is constant and radial. The effect on thermal anisotropies might also be important. The magnitudes of the effects depend on presently unknown correlations between fluctuations in the solar wind.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 3; Mar. 197
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  • 64
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    Observations of a high-energy ion shock spike in interplanetary space (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Observations are reported of a high-energy ion shock spike extending in energy to more than 25 MeV for protons, more than 4.3 MeV/nuc for alpha particles, and more than 1.6 MeV/nuc for medium nuclei with Z of at least 6. The measurements were obtained in the course of a solar-particle event on September 15, 1975, by the IMP-7 and IMP-8 spacecraft. It is shown that the observations can be reasonably accounted for by intensive acceleration of charged particles at an 'almost' perpendicular interplanetary shock wave. The data are inconsistent with a one-step d.c.-type acceleration process.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 3; Mar. 197
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  • 65
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    Multistream and Monte Carlo calculations of the sun's aureole (1976)
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    Publication Date: 2019-06-27
    Description: The scattered UV intensities in the sun's aureole are calculated using both a multi-stream scattering method and a Monte Carlo approach. Angular distributions for both Rayleigh and aerosol scatterings are obtained with a realistic atmospheric model. Moderate- and sharply-forward-peaked phase functions of aerosol scattering, corresponding to realistic analytic size distributions, are incorporated. Results from the two independent calculations are in reasonable agreement for a realistic atmospheric model. The results indicate that the scattered UV intensity in the sun's aureole is about four orders smaller than the transmitted intensity while the scattered intensity for pure Rayleigh scattering is only 1-10 millionths times that of the transmitted sun. Based on these intensity ratios, we estimate that the integrated scattered contributions from the aureole to a well-collimated sun photometer of acceptance aperture 2-3 deg are below about 1% of the direct contribution.
    Keywords: SOLAR PHYSICS
    Type: Journal of the Atmospheric Sciences; 33; Mar. 197
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  • 66
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    Structure of the solar chromosphere. II - The underlying photosphere and temperature-minimum region (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The paper presents a non-LTE empirical model of the quiet solar photosphere and the temperature-minimum region. The continuous spectrum computed from this model is in good overall agreement with available disk-center observations throughout the wavelength range from 0.125 to 500 microns. It is found that (1) absolute-intensity measurements are needed in the range between 1 and 2 microns to establish the structure of the deepest observable layers; (2) absolute-intensity or flux measurements are needed in the range between 20 and 200 microns to determine whether the minimum solar temperature occurring between the photosphere and the chromosphere is as low as indicated by present observations or much higher, as recent theoretical predictions indicate; (3) studies of the far-ultraviolet spectrum based on the assumption of LTE can be substantially in error; and (4) line opacity seems to account for the 'missing opacity' in the ultraviolet.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal Supplement Series; 30; Jan. 197
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  • 67
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    Hydraulic concentration of magnetic fields in the solar photosphere. III - Fields of one or two kilogauss (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Detailed analysis of weak and strong lines suggests that the magnetic fields in isolated intense flux tubes in supergranule boundaries in the solar photosphere may be as large as 2000 gauss. This paper is a concise systematic review of hydrodynamic effects that might compress a magnetic field to great intensity. The properties of force-free fields are reviewed to show that they do not contribute to concentration of magnetic fields, in spite of the popular notion to the contrary. Of the seven effects considered, it is concluded that only cooling of the gas within the field can produce the high field densities inferred from observation. It is shown that inhibition of convection appears not to possess the necessary qualitative cooling features and that overstability, generating transverse hydromagnetic waves - essentially Alfven waves - is the only way to account for the cooling and field intensification.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 204; Feb. 15
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  • 68
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    Spectroscopic evidence for a higher rotation rate of magnetized plasma at the solar photosphere (1976)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 203; Feb. 1
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  • 69
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    A two-region model of the solar wind including azimuthal velocity (1976)
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    Publication Date: 2019-06-27
    Description: The two-region model of the solar wind divides the interplanetary space into two regions: it assumes that the solar wind is one-fluid in an inner region within 0.4 AU and two-fluid in an outer region beyond 0.4 AU. This paper includes the angular motion of the solar wind in the two-region model. The flow in the one-fluid region is governed by the one-fluid magnetohydrodynamic equations. The second and third moment equations of the Vlasov equation together with other conservation equations are used to describe the solar-wind flow in the two-fluid region. The predicted azimuthal velocity at 1 AU is less than 2 km/s. All other macroscopic and microscopic properties from this model are in good agreement with experimental quiet-time observations at 1 AU. The numerical results also confirm that when the azimuthal velocity is included in the analysis, the amount of magnetic-field energy converted into kinetic energy in the solar wind is only a small fraction of the total expansion energy flux and has little effect upon the final radial expansion velocity.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 203; Feb. 1
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  • 70
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    On the high correlation between long-term averages of solar wind speed and geomagnetic activity (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Six-month and yearly averages of solar-wind speed from 1962 to 1975 are shown to be highly correlated with geomagnetic activity as measured by averages of the Ap index. On the same time scale the correlation between the southward component of the interplanetary magnetic field and geomagnetic activity is poor. Previous studies with hourly averages gave opposite results. The better correlation with the southward component on an hourly time scale is explained by its large variation compared with the relatively constant solar-wind speed. However, on a yearly time scale the magnitude of the variations in both parameters are about the same. This problem can be solved by invoking an energy transfer mechanism which is proportional to the first power of the southward component and a higher power of the solar-wind speed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 82; May 1
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  • 71
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    The solar gamma-ray spectrum between 4 and 8 MeV (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The properties of nuclear gamma-ray emission in the 4-8-MeV range are evaluated in detail. This emission consists of broad and narrow lines resulting from nuclear reactions of energetic H, He, C, and O nuclei with ambient matter. From a comparison of the calculations with observations of the August 4, 1972, flare, it is concluded that: (1) essentially all the observed radiation in the 4- to 8-MeV region is due to the superposition of broad and narrow lines of nuclear origin with almost no contribution from other mechanisms; (2) the accelerated particles in the energy region from about 10 to 100 MeV/amu have a relatively flat energy spectrum; (3) the calculated gamma-ray spectrum obtained from an isotropic distribution of accelerated particles fits the observed spectrum better than the spectrum derived from an anisotropic distribution for which the velocity vectors of the particles point toward the photosphere; and (4) it is possible to set a stringent upper limit on the ratio of relativistic electrons to protons in flares, consistent with the small but finite electron-to-proton ratio in galactic cosmic rays.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 214
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  • 72
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    A comment on the acceleration of charged particles in the presence of micro-turbulence as related to solar flares (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Mar. 197
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  • 73
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    Infrared continuum observations of five-minute oscillations (1977)
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    Publication Date: 2019-06-27
    Description: Infrared continuum observations of the sun at wavelengths between 10 and 30 microns show a nonisothermal response of the upper photosphere to compression waves associated with the five-minute oscillations. Observations were made with four broad-band filters with effective transmission wavelengths between 10 and 26 microns and with a 10 arcsec aperture. Further observations at submillimeter wavelengths with a 2-arcmin aperture did not resolve oscillatory fluctuations of five-minute period. Comparisons with velocity-field data of Howard (1976) suggest that the relaxation time of the photosphere exceeds (300/2 pi) seconds at the height of formation of the 26-micron continuum. The photosphere reponds to 3-mHz oscillatory motion with considerably less compression than expected for simple acoustic modes in an adiabatically responsive atmosphere, confirming the evanescent character of the five-minute oscillations.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 52; May 1977
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  • 74
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    High coronal structure of high velocity solar wind stream sources (1977)
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    Publication Date: 2019-06-27
    Description: It is shown analytically that the transition from a high-speed stream source to the ambient coronal conditions is quite rapid in longitude in the high corona. This sharp eastern coronal boundary for the solar wind stream sources is strongly suggested by the solar wind 'dwells' which appear in plots of solar wind velocity against constant-radial-velocity-approximation source longitudes. The possibility of a systematic velocity-dependent effect in the constant-radial-velocity approximation, which would cause this boundary to appear sharper than it is, is investigated. A velocity-dependent interplanetary propagation effect or a velocity-dependent 'source altitude' are two possible sources of such a systematic effect. It is shown that, for at least some dwells, significant interplanetary effects are not likely. The variation of the Alfvenic critical radius in solar wind dwells is calculated, showing that the high-velocity stream originates from a significantly lower altitude than the ambient solar wind.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Mar. 197
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  • 75
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    Brightness distributions of the sun at 33 and 37 GHz (1977)
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Mar. 197
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  • 76
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    High resolution mapping of the magnetic field of the solar corona (1977)
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    Publication Date: 2019-06-27
    Description: The mapping of the current-free magnetic field of the solar corona and the reliability of the spherical harmonic analysis of the photospheric magnetic field pattern are improved by data with much greater dynamic range and spatial resolution than previously available and a new algorithm which permits spherical harmonic expansion to a much higher value of the principal index. Coronal field maps can be drawn for local regions, for just the open field lines, and for various spatial resolutions on a global scale.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Mar. 197
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  • 77
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    The embedded feature model for the interpretation of chromospheric contrast profiles (1977)
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    Publication Date: 2019-06-27
    Description: Contrast profiles obtained from chromospheric filtergrams and spectra of bright and dark mottles have to date been interpreted almost exclusively in terms of Becker's cloud model. Here we demonstrate the failure of this model to account in a physically consistent way for the observed contrasts. As an alternative, we introduce an embedded-feature model, restricting our discussion in this paper to stationary features. Our model is then characterized by three independent parameters: the density of absorbing atoms, the geometrical depth, and the profile of the absorption coefficient. An analytic approximation to the contrast resulting from such a model reproduces well the observed behavior of all types of contrast profiles.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 213
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  • 78
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    Comparison of flare bremsstrahlung resulting from energetic thermal and nonthermal electrons (1977)
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    Publication Date: 2019-06-27
    Description: The paper investigates the behavior of the X-ray bremsstrahlung spectra resulting from two distinct types of electron distribution functions impinging on a target atmosphere during flare activity. A power-law distribution function is compared with two double-peaked Maxwellians. The results of these calculations show that it would be difficult to rule out multithermal interpretations for the emitted high-energy X-rays.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Jan
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  • 79
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    A reexamination of solar upper photosphere models, the calcium abundance, and empirical damping parameters (1977)
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    Publication Date: 2019-06-27
    Description: A general iterative method is described for constructing thermal models of the solar photosphere consistent with observed strong and weak lines of Ca I and Ca II. Calibrations of the solar calcium abundance and the van der Waals parameter for important Ca I and Ca II lines are obtained using plane-parallel largely LTE model atmospheres, and these thermal models are modified for better fits to the measured Ca II H and K inner wing shapes. Possible sources of error in this semiempirical approach are evaluated. The derived hydrogen van der Waals broadening is compared with theoretical estimates of that broadening as well as with experimental measurements of the helium broadening
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 213
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  • 80
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    6 centimeter observations of solar active regions with 6 sec resolution (1977)
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    Publication Date: 2019-06-27
    Description: We have used the Westerbork Synthesis Radio Telescope for observations of solar active regions at 6 cm during 1974 May 8-10. The particular problems of using a sidereal instrument for solar observations are discussed. Maps of total intensity and circular polarization were obtained for four active regions with sunspots and a plage region; the linear polarization was below the noise limit. The brightest components of the 6 cm emission are associated with sunspots, while weaker components are associated with the plage magnetic fields, both longitudinal and transverse. An inversion of the sense of circular polarization was observed in the preceding part of a region with bipolar magnetic-field structure, about two days after the region passed through the central meridian. Nine bursts were also observed, and their one-dimensional positions with respect to the associated active regions are given.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 213
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  • 81
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    Physics of an active region loop system (1977)
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    Publication Date: 2019-06-27
    Description: The structure of the active region loops is investigated by the study of a loop complex which undergoes a dramatic evacuation of most of the mass it contains. The need for continual energy deposition in loops is emphasized by the apparent cessation of energy input to the loops studied and their subsequent behavior. Estimates are made of the energy necessary to form and to maintain the loops, and of the relative importance of radiation and thermal conduction as energy loss mechanisms. Models based on the observed EUV emission are used to place limits on the size of loops seen in various lines and on the density and temperature structure. It is found that the cool cores of active region loops are likely to be no more than a few hundred kilometers in radius and that several such cool threads may be imbedded in a common hot outer sheath. The primary energy loss on a large scale is radiation with thermal conduction contributing to local disturbances. There is a tendency for the development of apparently unstable condensations or knots along the length of a loop.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 51; Jan
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  • 82
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    Exact Green's function method of solar force-free magnetic-field computations with constant alpha. I - Theory and basic test cases (1977)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Exact closed-form solutions to the solar force-free magnetic-field boundary-value problem are obtained for constant alpha in Cartesian geometry by a Green's function approach. The uniqueness of the physical problem is discussed. Application of the exact results to practical solar magnetic-field calculations is free of series truncation errors and is at least as economical as the approximate methods currently in use. Results of some test cases are presented.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 212
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  • 83
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    Spectroscopic studies of the solar corona at X-ray wavelengths (1976)
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    Publication Date: 2019-06-27
    Description: The spatial distribution of emission in several X-ray lines is discussed with emphasis on temperature dependence and association with active regions. Results are presented for the trio of helium-like O VII lines which demonstrate (1) a spatial variation in the density-dependent forbidden-to-intersystem line ratio, and (2) a strong spatial variation in the intensity of the O VII resonance line relative to the optically forbidden transitions. The second effect appears to be caused by resonance scattering by material in the line of sight.
    Keywords: SOLAR PHYSICS
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  • 84
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    Evidence of a large-scale gradient in the solar wind velocity (1976)
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    Publication Date: 2019-06-27
    Description: Measurements of the solar wind velocity are compared at two widely separated locations, using plasma data obtained by Mariner 5, en route to Venus, and with the near-earth satellites Explorer 33, 34, and 35. A previous study of the propagation of interplanetary sector boundaries between Mariner and the earth had implied the existence of large scale velocity gradient which was interpreted as a latitude gradient of approximately 13 km/sec per degree of latitude. The results of the present investigation in which the earlier results were extended to the overall solar wind, without regard to the presence of sector boundaries, suggests that a latitude dependence of the solar wind velocity is the most plausible interpretation of the large-scale velocity gradient.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; May 1
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  • 85
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    Solar limb brightening in submillimeter wavelengths (1976)
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    Publication Date: 2019-06-27
    Description: Differential two-beam scans of the sun in submillimeter wavelengths (350 microns to 1 millimeter) indicate limb brightening approaching 1 percent when the cosine of the angle from the normal equals 0.60. The observations also show considerable chromospheric structure, both in active and quiet regions, but with less relative amplitude than at millimeter and centimeter wavelengths. The limited angular resolution of the observing system, together with photometric errors due to fluctuating atmospheric transparency, make the brightness profile of the extreme limb uncertain. The observed degree of limb brightening is considerably less than that consistent with spherically symmetric model atmospheres based on continuum brightness-temperature measurements. The suppression of limb brightening suggests the existence of irregular granular structure with both horizontal and vertical characteristic sizes of the order of 1500 km. High-resolution images in the wings of the K-line show granular structure of about this horizontal scale.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 203; Feb. 1
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  • 86
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    Non-LTE profiles of strong solar lines (1976)
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    Publication Date: 2019-06-27
    Description: The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.
    Keywords: SOLAR PHYSICS
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4,; p 110-122
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  • 87
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    Results of coronal hole research: An overview (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: An overview of the last 10 years of coronal hole research, in particular since 1970, is presented. The findings of the early investigations and the more recent results obtained with Skylab/Apollo Telescope Mount instrumentation are discussed.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-73317
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  • 88
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    Observations of limb flares with a soft X-ray telescope (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The structure and evolution of 26 limb flares have been observed with a soft X-ray telescope flown on Skylab. The results are: (1) One or more well defined loops were the only structures of flare intensity observed during the rise phase and near flare maximum, except for knots which were close to the resolution of the telescope; (2) the flare core features were always sharply defined during rise phase; and (3) for the twenty events which contained loops, the geometry of the structure near maximum was that of a loop in ten cases, a loop with a spike at the top in four cases, a cusp or triangle in four cases, and a cusp combined with a spike in another two cases. Based on observation of the original film, it is suggested that flares which underwent large scale deformations had become unstable to MHD kinks. This implies that these flares occurred in magnetic flux tubes through which significant currents were flowing.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-144329 , ATR-76(7405)-2
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  • 89
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    A direct measurement of the charge states of energetic iron emitted by the sun (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The charge states of energetic iron have been measured directly for the first time in a solar particle event. In the energy interval 0.01 to 0.25 MeV per nucleon, iron is not fully stripped but has a mean ionization state of 11.6. This value is remarkably similar to the mean ionization state of iron in the quiet solar wind and suggests that the charge states were "frozen-in" at a coronal temperature of approximately 1,500,000 K.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-148144 , TR-76-113 , PUBL-76-259
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  • 90
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    Time dispersion of energetic solar particles, unexpected velocity and species dependence (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The intensity-time behavior for protons and helium, as well as for carbon, oxygen and iron ions was measured following the 1974 September 19 solar flare for energies between 0.5 and approximately 5 MeV per nucleon. The profiles displayed a time dispersion which is inversely proportional to velocity for each individual species. In addition, at a given velocity the time dispersion also depended on the charge to mass ratio of the ion. Based on this latter dependence, it was concluded that while carbon and oxygen are essentially fully stripped, iron nuclei are not, having an effective charge Q = 10 + or - 5. The observed dispersion cannot be explained by purely rigidity dependent diffusive propagation.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-148143 , TR-76-114 , PHYSICS-PUB-76-260
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  • 91
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    A solar flare bibliography for 1973 through 1975 (1976)
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    Publication Date: 2019-06-27
    Description: The open literature for 1973 through 1975 was searched for publications with flare information that might pertain to the analysis of the Skylab data. The resulting bibliography is divided into three sections: (1) results from Skylab, (2) results from ground-based data during the Skylab time period, (3) other pertinent publications.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-73312
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  • 92
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    Magnetohydrodynamic and gasdynamic aspects of solar-wind flow around terrestrial planets: A critical review (1976)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Problems in space physics are discussed whose models, in simplified form, reduce to a supersonic flow scheme with a detached shock wave, namely: (1) solar wind interaction with an intrinsic planetary magnetic field; (2) solar wind interaction with the ionized component of the atmosphere of a comet; and (3) solar wind interaction with the ionosphere of a planet which does not possess its own magnetic field. The numerical study of the above problems is performed with the use of magnetogasdynamic equations for an ideal single fluid model. From the physical veiwpoint, the problems are solved in terms of as simple phenomena as possible; the principal objective is to make recently developed methods of numerical analysis of mixed flows applicable to space physics problems.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Solar-Wind Interaction with the Planets Mercury, Venus, and Mars; p 135-149
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  • 93
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    Magnetic holes in the solar wind (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An analysis is presented of high resolution interplanetary magnetic field measurements from the magnetometer on Explorer 43 which showed that low magnetic field intensities in the solar wind at 1 AU occur as distinct depressions or 'holes'. These magnetic holes are new kinetic-scale phenomena, having a characteristic dimension on the order of 20,000 km. They occurred at a rate of 1.5/day in the 18-day time span (March 18 to April 6, 1971) that was analyzed. Most of the magnetic holes are characterized by both a depression in the absolute value of the magnetic field, and a change in the magnetic field direction; some of these are possibly the result of magnetic merging. However, in other cases the magnetic field direction does not change; such holes are not due to magnetic merging, but might be a diamagnetic effect due to localized plasma inhomogeneities.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-71109 , X-692-76-90
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  • 94
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    Three dimensional aspects of interplanetary shock waves (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Most of the interplanetary shock waves observed with 1 AU of the sun originate from some short lived solar event, such as a solar flare, and then propagate out as a more-or-less spherical shock wave until they leave the solar system. Beyond 1 AU another class of interplanetary shock wave becomes common--the corotating shock pair formed by the interaction of long lived solar wind streams. The three dimensional geometry of these two classes of interplanetary shocks is discussed. Also discussed are how these geometries can be statistically studied with an out-of-the-ecliptic mission. Diagrams of shock wave propagation are shown. Also given are numerical examples of shock wave propagation.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Proc. of the Symp. on the Study of the Sun and Interplanetary Medium in Three Dimensions; p 166-187
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  • 95
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    H alpha observations of the 12 August 1975 type 3-RS bursts (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: H alpha filtergram observations of a number of the Type III-RS (reverse slope) bursts that occurred on August 12, 1975 are presented. Solar radio emission was peculiar on that date in that a large number, and proportion, of the usually rare reverse slope bursts were observed. The radio bursts are shown to coincide in time with a homologous set of H alpha flares located at the limbward edge of spot group Mt. Wilson 19598. A model is proposed in which the reverse slope bursts are the downward branches of U bursts, whose upward branches are hidden behind the coronal density enhancement over the spot group.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-147098 , BBSO-0155
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  • 96
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    AE 6: A model environment of trapped electrons for solar maximum (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A projected inner zone electron model environment, AE 6, for the epoch 1980 is presented. It is intended to provide estimates of mission fluxes that spacecraft will encounter in the coming solar maximum years. AE 6 is presented by graphs of omnidirectional integral flux as a function of L shell, the ambient magnetic field B, and the energy E. Results of orbital integrations for altitudes from 150 n.m. to 18,000 n.m. are given for circular orbits with four different inclinations, using the AE 6 and the AE 4 solar maximum models for the inner and outer zones, respectively. The derivation of AE 6 is described, and a brief comparison is given of the radial profiles of equatorial fluxes from several related models. A short summary of the associated computer programs is included.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-72597 , NSSDC/WDC-A-R&S-76-04
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  • 97
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    Atlas of Skylab ATM/S056 super-long exposures and stepped-image frames (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A description is given of Skylab and exposure information regarding the S-L pictures is tabulated. Frames which display stepped images are identified.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-64992
    Format: application/pdf
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  • 98
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    Gamma-ray and microwave evidence for two phases of acceleration in solar flares (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Relativistic electrons in large solar flares produce gamma ray continuum by bremsstrahlung and microwave emission by gyrosynchrotron radiation. Using observations of the 1972, August 4 flare, the electron spectrum and the physical properties of the common emitting region of these radiations were evaluated. Information was also obtained on energetic protons in this flare by using gamma ray lines. From the electron spectrum, the proton-to-electron ratio, and the time dependences of the microwave emission, the 2.2 MeV line and the gamma ray continuum, it was concluded that in large solar flares relativistic electrons and energetic nuclei are accelerated by a mechanism which is different from the mechanism which accelerates approximately less than 100 keV electrons in flares.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-71083 , X-660-76-58
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  • 99
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    Atlas of Skylab ATM/S056 coronal hole observations (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An atlas of coronal hole observations (Patrol Long and Single Frame Long Filter 3) recorded by the Skylab Apollo Telescope Mount/SO56 X-ray Telescope during the first two manned missions is presented. A total of 279 operations (excluding super long frames) were determined. Comparisons are made between coronal hole observations performed in the first manned mission and those in the second manned mission, and between a super long filter 3 image and a typical single frame (or Patrol) long image. Additional studies to enhance the S056 coronal hole observations and perhaps to extend coverage into the last manned mission are suggested. The data presented are in preliminary form.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-64994
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  • 100
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    Simple analytical solutions for spherically symmetric production and modulation of energetic solar particles (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Exact analytical solutions are presented for the standard time-independent spherically symmetric convection-diffusion-adiabatic deceleration equation governing the transport of cosmic rays in the interplanetary medium for the case in which particles are produced with spherical symmetry at the sun. It is assumed that the solar-wind speed is constant and radial, and that the spatial diffusion coefficient has a power-law dependence on momentum. The Green's function describing the modulation of a monoenergetic production of particles is presented. The solutions provide a useful basis for the study of time-integrated properties of energetic solar-flare particle spectra.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 218
    Format: text
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