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  • Inorganic Chemistry  (723)
  • Organic Chemistry  (659)
  • Cell & Developmental Biology
  • SOLAR PHYSICS
  • 1975-1979  (1,865)
  • 1945-1949
  • 1975  (1,865)
Collection
Keywords
Publisher
Years
  • 1975-1979  (1,865)
  • 1945-1949
Year
  • 1
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    Correlation of Doppler noise during solar conjunctions with fluctuations in solar activity (1975)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Deviations betweeb observed Doppler noise and the noise model during solar conjunction were analyzed. It is tentatively concluded that these deviations are due to short-term fluctuations in solar activity as seen along the signal path, and not to solar/antenna structure effects or system noise temperature.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 264-272
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  • 2
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    Analysis and prediction of Doppler noise during solar conjunctions (1975)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The results of a study of Doppler data noise during solar conjunctions were presented. During the first half of 1975, a sizeable data base of Doppler data noise (estimates) for the Pioneer 10, Pioneer 11, and Helios 1 solar conjunctions was accumulated. To analyze this data, certain physical assumptions are made, leading to the development of a geometric parameter ("ISI") which correlates strongly with Doppler data noise under varying sun-earth-spacecraft geometries. Doppler noise models are then constructed from this parameter, resulting in the newfound ability to predict Doppler data noise during solar conjunctions, and hence to additionally be in a position to validate Doppler data acquired during solar conjunctions.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 231-263
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  • 3
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    Prognoz reports (1975)
    In:  CASI
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    Publication Date: 2006-01-11
    Description: Studies conducted outside the effect of the earth's magnetic field during the revolution period by the Prognoz satellite are examined. In particular, the unperturbed solar wind, the flux of charged particles continually given off the sun is studied. Solar activity and its effects on various natural phenomena are discussed.
    Keywords: SOLAR PHYSICS
    Type: Mod. Achievements of Cosmonautics (NASA-TT-F-16221); p 57-62
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  • 4
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    Plasma processes in the expansion of the solar wind and in the interplanetary medium (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Recent research into plasma processes involved in the expansion of the solar wind and the interplanetary medium is reviewed. Emphasized topics deal primarily with processes that drive the solar wind, the gross expansion of the interplanetary medium between 0.5 and 5 AU, recent observational results in the vicinity of 1 AU, and the microstructure of the interplanetary medium. Satellite measurements of the radial profile of the interplanetary medium out to 5 AU are discussed together with model calculations of the solar wind and its possible driving mechanisms. Studies of Alfven and magnetoacoustic waves in the solar wind are summarized. Possible roles are considered for thermal conduction in coronal energy transport, and observations of ion velocity distributions near 1 AU are described.
    Keywords: SOLAR PHYSICS
    Type: Reviews of Geophysics and Space Physics; 13; July 197
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  • 5
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    Observation of subordinate 2p/5/4d-2p/5/3p transitions in neon-like ions from Ca XI to Ni XIX (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Subordinate 2p(5)4d-2p(5)3p transitions in the neon-like ions from Ca XI through Ni XIX are identified. Such transitions between excited levels have not previously been reported for ionization stages higher than Al IV, although the resonance lines are known through Zn XXI in the neon isoelectronic sequence. Measurement of the solar flux in such transitions may aid in establishing the relative importance of the several cascade processes giving rise to the observed Fe XVII resonance lines.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; Aug. 1
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  • 6
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    Interplanetary gas. XXI - Validity of the Chapman-Enskog description of the solar wind for protons (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; Aug. 1
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  • 7
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    Study of He I emission lines in the solar atmosphere. III - The triplet-singlet line intensity ratios in solar prominences (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 40; 4, Ma; May 1975
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  • 8
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    Pioneer 10 measurements of the charge and energy spectrum of solar cosmic rays during 1972 August (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 15
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  • 9
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    The 1640.4 A H-alpha line of He II observed from Skylab (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Profiles obtained from NRL Skylab solar spectra of the 1640.4 A feature identified as the H-alpha line of He II are discussed and compared with theoretical profiles derived assuming (1) collisional excitation and (2) radiative recombination as the dominant excitation mechanism. Relative intensities of this line as a function of altitude above and below the solar white-light limb are also given for a representative quiet sun region and for a polar coronal hole.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 1
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  • 10
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    Temperature dependence of emission measure in solar X-ray plasmas. I - Nonflaring active regions (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Previous determinations of the form of the emission-measure distribution function for solar active regions are examined. It is found that two analyses in particular are affected by low quality of either observational or atomic data. An alternative method of analysis is discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 1
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  • 11
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    Effects of convection electric field on the distribution of ring current type protons (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The topology of the boundaries of penetration (or, inversely, the boundaries of the forbidden regions) of 90-deg pitch-angle equatorial protons with energies less than 100 keV are explored for an equatorial convection E-field which is directed in general from dawn to dusk. Due to the dependence of drift path on energy (or magnetic moment), complex structural features are expected in the proton energy spectra detected by satellites since the penetration distance of a proton is not a monotonically increasing or decreasing function of energy. During a storm when the convection E is enhanced, model calculations predict elongations of the forbidden regions analogous to tail extensions of the plasmasphere. Following a reduction in the convection field, spiral-structured forbidden regions can occur. Structural features inherent to large-scale convection field changes may be seen in the nose-like proton spectrograms observed near dusk by instrumentation on Explorer 45. These nose events are modelled by using an electric field model developed originally by Volland (1973). The strength of the field is related to the Kp index through night-time equatorial plasmapause measurements.
    Keywords: SOLAR PHYSICS
    Type: Planetary and Space Science; 23; July 197
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  • 12
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    The acceleration of heavy nuclei in solar flares (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The overabundance of heavy nuclei in solar cosmic rays of energy below about 10 MeV/nucleon is explained by taking into account the pre-flare ionization states of these nuclei in the region where they are accelerated. A model is proposed which considers two-step accelerations associated with the initial development of solar flares. The first step is closely related to the triggering process of flares, while the second one starts with the development of the explosive phase. Further ionization of medium and heavy nuclei occurs through their interaction with keV electrons accelerated by the first-step acceleration. It is suggested that the role of these electrons is important in producing fully ionized atoms in the acceleration regions.
    Keywords: SOLAR PHYSICS
    Type: Planetary and Space Science; 23; June 197
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  • 13
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    Equivalent width of molecular lines in stars. I - Lyman and Werner bands of H2 in the solar atmosphere (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 14
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    Solar particle events with anomalously large relative abundance of He-3 (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Energetic particle data are presented from a series of solar flares with a relative abundance of He-3 much higher than that of any previous events. The abundance of protons relative to He nuclei was significantly low in these events; not more than four H-2 and three H-3 were detected during the entire period under study, compared with 1110 He-3 nuclei. Results from these experiments are compared with data available from other investigations, and the limitations the former observations place on theoretical models to explain He-3-rich flares are discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 198; May 15
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  • 15
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    Heavy solar cosmic rays in the January 25, 1971 solar flare (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A detailed study of the charge composition of heavy solar cosmic rays measured in the January 25, 1971 solar flare including differential fluxes for the even-charged nuclei from carbon through argon is presented. The measurements are obtained for varying energy intervals for each nuclear species in the energy range from 10 to 35 MeV per nucleon. In addition, abundances relative to oxygen are computed for all the above nuclei in the single energy interval from 15 to 25 MeV per nucleon. This interval contains measurements for all of the species and as a result requires no spectral extrapolations. An upper limit for the abundance of calcium nuclei is also presented. These measurements, when combined with other experimental results, enable the energy dependence of abundance measurements as a function of nuclear charge to be discussed. It is seen that at energies above about 10 MeV per nucleon, the variations of abundance ratios are limited to about a factor of 3 from flare to flare, in spite of large variations in other characteristics of these solar events.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 16
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    The last OSO satellite (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Missions planned for OSO-8 are outlined. Instruments to be included on the satellite comprise a multichannel UV spectrometer, a high-resolution UV spectrometer, an X-ray crystal spectrometer and polarimeter, a hard X-ray telescope, a celestial X-ray spectrometer, a mapping X-ray heliometer, an extrasolar extreme UV monitor, and a soft X-ray telescope. The instruments make up a scientific payload that is larger, transmits data at a greater rate, can be pointed with higher accuracy, and has much better spatial and spectral resolution over a wider range of wavelengths than any payload carried by previous OSO satellites.
    Keywords: SOLAR PHYSICS
    Type: Sky and Telescope; 49; June 197
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  • 17
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    Observations at 6 cm of the solar active region (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Preliminary results are reported for the synthesis of a solar active region from observations with a synthesis radio telescope at a wavelength of 6 cm. Several individual sources are observed in the total-intensity and circular-polarization maps. These are shown to correspond to two large sunspots, two groups of small sunspots, and a plage. A magnetogram indicates that this active region had a bipolar structure with positive polarity concentrated on the main sunspots and negative polarity scattered over the plage and some of the small sunspots. It is noted that several radio bursts were recorded during the observation period and that one corresponded to a H-alpha flare near one of the sunspot groups.
    Keywords: SOLAR PHYSICS
    Type: Nature; 257; Oct. 9
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  • 18
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    Seasonal variation and magnitude of the solar sector structure-atmospheric vorticity effect (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Evidence is reported for a seasonal variation in the effect of solar sector structure on terrestrial atmospheric vorticity. Graphs showing average response of the 50,000-Pa vorticity area index to solar magnetic sector structure during the time interval extending from 6 days before to 6 days after the time at which a sector boundary is swept past the earth indicate that a 10% drop in the average value occurs at the time of passage, but this effect is observed only during the winter months.
    Keywords: SOLAR PHYSICS
    Type: Nature; 255; June 12
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  • 19
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    An anticorrelation between polar and equatorial rotation of the solar photosphere (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Published spectroscopic measurements of solar rotation are analyzed to show that when the rotation velocity increases at high latitudes it tends to decrease at low latitudes, and that when the rotation velocity decreases at high latitudes it increases at low latitudes. The high-latitude velocities typically vary over only 20% of the range of those near the equator and the smallest variations of all occurred near latitude 60 deg during the rising portion of the previous solar cycle. The anticorrelation is consistent with a recent suggestion that differential rotation on the sun arises from photospheric wind systems whose strength is determined, ultimately, by oscillations within the sun.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 20
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    A model for the origin of solar wind stream interfaces (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The basic variations in solar wind properties that have been observed at 'stream interfaces' near 1 AU are explained by a gas dynamic model in which a radially propagating stream, produced by a temperature variation in the solar envelope, steepens nonlinearly while moving through interplanetary space. The region thus identified with the stream interface separates the ambient solar wind from the fresh hot material originally in the stream. However, the interface regions given by the present model are thicker than most stream interfaces observed in the solar wind, a fact suggesting that some additional physical process may be important in determining that thickness. Variations in the density, speed, or Alfven pressure alone appear not to produce streams with such an interface.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; May 1
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  • 21
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    Interplanetary streams and their interaction with the earth (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Plasma and magnetic field observations of interplanetary streams near 1 AU are summarized. Two types of streams have been identified - corotating streams and flare-associated, and other flow patterns are present due to interactions among streams. The theory of corotating streams, which attributes them to a high temperature region near the sun, satisfactorily explains many of the effects observed at 1 AU. A correspondingly complete theory of flare-associated streams does not exist. Streams are a key link in the chain that connects solar and geomagnetic activity. The factors that most influence geomagnetic activity are probably related to streams and determined by the dynamics of streams. The evolution of streams on scales of 27 days and 11 years probably determines the corresponding variations of geomagnetic activity.
    Keywords: SOLAR PHYSICS
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  • 22
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    The variation of solar proton energy spectra and size distribution with heliolongitude (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A statistical study of the initial phases of a large number of solar particle events provides an approach for an investigation of the variability in the production process and coronal diffusion. A description is given of the procedures which are suitable for identifying the parent flare of an event, taking into account the heliocentric distribution of the flare-associated events. The determination of the proton energy spectrum at the sun is discussed along with the variation of the spectral index with the associated flare heliocentric longitude, questions concerning the source spectra and the acceleration process, and the size distribution of flare associated particle events.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Mar. 197
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  • 23
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    One- and multi-component models of the upper photosphere based on molecular spectra. IV - Non-LTE treatment of the CN violet system (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Mar. 197
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  • 24
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    Differences between the bulk speeds of hydrogen and helium in the solar wind (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; Apr. 1
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  • 25
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    The reconnection of magnetic field lines in the solar corona (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Skylab XUV coronal spectroheliograms and photospheric magnetograms are compared. This comparison shows that, as new bipolar magnetic fields emerge through the solar surface into the corona, the new coronal fields interact with the old ones in a manner that suggests the reconnection of the field lines.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 196; Mar. 15
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  • 26
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    Interplanetary gas. XX - Does the radial solar wind speed increase with latitude (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The astrometric technique used to derive solar wind speeds from ionic comet-tail orientations has been used to test the suggestion that the radial solar wind speed is higher near the solar poles than near the equator. We find no evidence for the suggested latitude variation.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 196; Mar. 15
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  • 27
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    Forbidden lines of highly ionized iron in solar flare spectra (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 196; Mar. 1
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  • 28
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    XUV observations of coronal magnetic fields (1975)
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    Publication Date: 2011-08-16
    Description: Spectroheliograms obtained with the Naval Research Laboratory's Extreme Ultraviolet Spectrograph (S082A) on Skylab are compared with Kitt Peak National Observatory magnetograms. A principal result is the characteristic reconnection of flux from an emerging bipolar magnetic region to previously existing flux in its vicinity. Examples of the disappearance of magnetic flux from the solar atmosphere are also shown. The results of a particularly simple, potential field calculation are shown for comparison with the Skylab observations.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 40; Jan. 197
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  • 29
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    On the planetary theory of sunspots (1975)
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    Publication Date: 2011-08-16
    Description: An investigation is conducted of the full tidal problem for Mercury, Venus, Earth, and Jupiter, the tide-raising planets, taking into account the complete orbital elements, including eccentricity, inclination, and their variation with time. Data for a comparison of tidal and sunspot dates are listed in a table. The investigation shows that the alignment of the tide-raising planets within 10 degrees is a common phenomenon, occurring approximately every 10.4 years. This alignment is not associated with drastic tidal effects.
    Keywords: SOLAR PHYSICS
    Type: Nature; 253; Feb. 13
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  • 30
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    Solar activity and its relation to certain parameters of phenomena in the geophysical complex (1975)
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    Publication Date: 2011-08-16
    Description: Results of a detailed analysis of solar activity in 1957-1965 are compared with the data on solar activity with variations of cosmic ray activity, and geomagnetic, ionospheric and terrestrial currents. Cosmic ray variations are investigated with reference to the asymmetry of solar hemispheres. All storms in the IGY are classified and a symbolic diagram of the time sequence is drawn up.
    Keywords: SOLAR PHYSICS
    Type: Cosmic Rays (; p 125-132
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  • 31
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    Solar and terrestrial physics (1975)
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    Publication Date: 2011-08-16
    Description: The effects of solar radiation on the near space and biomental earth, the upper atmosphere, and the magnetosphere are discussed. Data obtained from the OSO satellites pertaining to the solar cycle variation of extreme ultraviolet (EUV) radiation are analyzed. The effects of solar cycle variation of the characteristics of the solar wind are examined. The fluid mechanics of shock waves and the specific relationship to the characteristics of solar shock waves are investigated. The solar and corpuscular heating of the upper atmosphere is reported based on the findings of the AEROS and NATE experiments. Seasonal variations of the upper atmosphere composition are plotted based on OGO-6 mass spectrometer data.
    Keywords: SOLAR PHYSICS
    Type: Significant Accomplishments in Sci. and Technol.; p 92-138
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  • 32
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    A newly observed solar feature - Macrospicules in He II 304 A (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: He II 304 A spectroheliograms, obtained with the NRL extreme-ultraviolet slitless spectrograph during the Skylab mission, show spikelike structures at the sun's polar limb which resemble the familiar H-alpha spicules. However, the relatively large size and long life of these He II features has led to distinguishing them by the name 'macrospicules'. The macrospicules appear as protuberances or jets, ranging from 5 to over 60 sec in length, from 5 to 30 sec in width, and from 5 to over 40 minutes in lifetime. Perhaps the most radical departure from H-alpha spicules is that macrospicules occur only within the chromospheric boundaries of coronal holes. Thus macrospicules are most easily visible over the solar poles due to the coronal holes normally present there, and much less frequently at lower latitudes during limb passage of relatively rare, low-latitude coronal holes.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 197; May 1
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  • 33
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    Causes of Forbush decreases and other cosmic ray variations (1975)
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    Publication Date: 2011-08-16
    Description: The relationship between neutron monitor variations and the intensity variations of the interplanetary magnetic field is studied by using Deep River data and Imp series satellite data. In over 80% of the cases studied in 1968, identifiable depressions of the cosmic ray intensity are associated with magnetic field enhancements of several hours duration and intensity above 10 gamma. Conversely, almost every magnetic field enhancement has an identifiable effect (though not necessarily a marked depression) on the cosmic ray intensity. Perpendicular gradient drifts are suggested as one possible mechanism producing the individual decreases, and some ideas on the recovery processes are presented. Long-lasting Forbush decreases are found to be the consequence of the action of several successive magnetic field enhancements. Evidence is presented that indicates that most of these enhancements are caused by the steepening of streams in interplanetary space.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; Feb. 1
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  • 34
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    The calculation of force-free fields from discrete flux distributions (1975)
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    Publication Date: 2011-08-16
    Description: This paper presents particularly simple mathematical formulas for the calculation of force-free fields of constant alpha from the distribution of discrete sources on a flat surface. The advantage of these formulas lies in their physical simplicity and the fact that they can be easily used in practice to calculate the fields. The disadvantage is that they are limited to fields of 'sufficiently small alpha'. These formulas may be useful in the study of chromospheric magnetic fields by the comparison of high-resolution H-alpha photographs and photospheric magnetograms.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 45; Dec. 197
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  • 35
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    Lunar magnetism (1975)
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    Publication Date: 2011-08-16
    Description: It is shown, for a very simple model of the moon, that the existence of a primordial core magnetic field would give rise to a present day nonzero dipole external field. In the investigation a uniformly magnetized core embedded in a permeable mantle is considered. The significance of the obtained results for the conclusions reported by Runcorn (1975) is discussed. Comments provided by Runcorn to the discussion are also presented.
    Keywords: SOLAR PHYSICS
    Type: Nature; 258; Nov. 13
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  • 36
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    The spatial and temperature structure of vacuum spark plasmas (1975)
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    Publication Date: 2011-08-16
    Description: The spatial and temperature structures of the X-ray emitting components of low-inductance vacuum-spark plasmas are investigated. The plasmas produced by low-inductance vacuum sparks show striking resemblances to solar-flare plasmas. High-resolution photographs show that the spark plasmas are composed of hot (about 30 million K) compact sources (less than 20 microns) and cooler (about 10 million K) larger sources (of the order of 100 microns). Both types of sources may be produced by the same plasma at different times. The differences between the solar flare iron-line spectrum near 1.9 A and the spark iron-line spectrum are discussed and interpreted.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 201; Oct. 1
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  • 37
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    Energy balance in a magnetically confined coronal structure observed by OSO-7 (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A model of a coronal region of enhanced Fe XV and Fe XVI emission is developed and its energy balance is examined using extreme ultraviolet observations from OSO-7 together with calculations of possible force-free coronal magnetic field configurations. The coronal emissions overlying the photospheric boundary between regions of opposite magnetic polarity are found to be associated with generally nonpotential (current-carrying) magnetic fields in the forms of arches with footpoints in regions of opposite polarity. The orientation of these arches relative to the neutral line changes with degree of ionization of the emitting ion (which we infer from our limb observations to be a function of height) and may be evidence of differing electric currents along various field lines. The appearance of a coronal arch, seen side-on, can conveniently be represented by a parabola and a detailed analysis shows this to be a realistic approximation that should be generally useful in analyzing two-dimensional pictures of coronal structures.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 38
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    Observation of possible Fe XVII 2p5 3p/1S0/ - 2p5 3s/1P1, 3P1/ transitions in spectra of a solar active region and flare (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Expected wavelengths and relative intensities are obtained from previous calculations for the hitherto unobserved transitions 2p5 3p(1SO) - 2p5 3s(1P1, 3P1) in Fe XVII. A candidate pair of lines at 197.05 A and 242.09 A was found in laboratory spectra and appears to be present in the spectra of a solar active region observed by the OSO-7 Goddard spectroheliograph as well as in the spectrum of a Skylab-observed solar flare.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; July 197
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  • 39
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    Abundance of Fe relative to H at 1.5 solar radii (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The abundance of Fe relative to H is obtained by using resonantly scattered intensities of lambda 284 of Fe XV that were measured with OSO-7 and resonantly scattered intensities of L-alpha of H I that were obtained by Gabriel (1971). Because of possible differences in electron densities along lines of sight for these non-simultaneous measurements and in relative calibrations, results are rather uncertain but still indicate that the average Fe abundance relative to H in the corona appears to be at least as large as a recent photospheric abundance. Some limitations in using this method for obtaining abundances are examined for future experiments with simultaneous measurements and well calibrated detectors.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 40
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    Radio evidence for an expanding magnetic arch beyond 20 solar radii (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; May 1975
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  • 41
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    The effect of primordial hydrogen/helium fractionation on the solar neutrino flux (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: If hydrogen and helium are immiscible below some critical temperature, gravitational separation could occur in the proto-sun, resulting in a nearly pure helium core and a nearly pure hydrogen shell. We have constructed solar models according to this scenario and find the neutrino flux reduced to 1.5-3 SNU.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 196; Mar. 1
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  • 42
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    The solar elongation distribution of low-frequency radio bursts (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Over 500 days of low-frequency (less than 1 MHz) radio observations from the IMP-6 spacecraft have been accumulated to produce a two-dimensional map (frequency vs elongation) of solar type III burst occurrences. This map indicates that most solar bursts in this frequency range are observed at the second harmonic of the plasma frequency, rather than the fundamental. The map also shows that the solar wind electron density varies as an inverse power of heliocentric distance, with the exponent somewhat less than 2 to perhaps 3 or higher.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 45; Nov. 197
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  • 43
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    Ultraviolet solar identifications based on extended absorption series observed in the laboratory spectrum of Si I (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The absorption spectrum of Si I in the wavelength region between 1500 and 1900 A has been photographed at high resolution. The silicon vapor was produced in a 122-cm-long King furnace at 1800 to 2300 C. Forty-two Rydberg series have been observed from the ground state terms 3p(2)3P and 1D to terms associated with the 3pns and 3pnd configurations. All of the series from these configurations with J less than 4 have been extended with the 3pnd 3D(3) levels reaching n = 56. Numerous perturbations have been observed. This laboratory work has provided the basis for extending the identification of silicon lines in the solar spectrum. Nearly all lines found in the laboratory spectrum are also found in rocket spectrograms of the solar chromosphere. More than 300 lines have been attributed to Si I. The excellent correlation between laboratory and solar Si I lines is illustrated.
    Keywords: SOLAR PHYSICS
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  • 44
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    A distinctive type of ascending prominence - 'Fountain' (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Cinematographic observations of solar prominences made at Mauna Loa, Hawaii, during the past few years suggest that there is a well-defined subclass of ascending prominences characterized by closed-system transference of chromospheric material along an arch or loop (up one leg and down the other). While this occurs, the entire prominence envelope steadily rises upward and expands through the corona. These prominences are denoted as 'fountains'. Several examples are described. Fountains appear to be well contained by coronal magnetic fields. Their total kinetic energy is of the order of 10 to the 30th power erg, but dissipation is typically quite slow (over time periods of 100 min or so), so that the correlative disturbances (radio bursts, coronal transients, chromospheric brightenings) are generally not spectacular or nonexistent.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 44; Oct. 197
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  • 45
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    Limb-brightening curves of XUV transition zone lines in the quiet sun and in a polar coronal hole observed from Skylab (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Solar limb-brightening curves are discussed for XUV spectral lines formed in the upper chromosphere and transition zone of a quiet region and a polar coronal hole. The spectra were recorded with a slit spectrograph on Skylab. The lines considered are emitted from ions formed within the temperature range from 10,000 to 220,000 K. The limb-brightening curves cover a region from -4 sec within the limb to +20 sec above it. The data from 0 sec to +20 sec are compared with predictions based on both homogeneous and inhomogeneous models of the transition zone. The limb-brightening curve of the O I line at 1355.6 A indicates that O I is formed in spicules. The limb brightening of the He II line at 1640.4 A is consistent with a temperature of formation between about 40,000 and 90,000 K for He II.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Dec. 15
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  • 46
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    The intensities and profiles of XUV transition zone lines in a quiet sun region compared to a polar coronal hole (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The intensities of XUV transition-zone lines from limb spectra of a quiet-sun region and a polar coronal hole are compared. The spectra were obtained with a slit spectrograph on Skylab and cover a region from -12 sec within the limb to 20 sec above it. The lines selected for comparison are formed at temperatures that range from 36,000 to 220,000 K. Lines of the higher-temperature ions, e.g. O v, are significantly less intense in the coronal hole, and lines of lower-temperature ions show little change. Profiles of selected optically thin transition-zone lines from the quiet-sun and coronal-hole spectra are also shown. The lines are broader than expected in ionization equilibrium, and bulk-motion velocities are deduced from the widths of the lines. There appears to be little, if any, statistically significant difference in the velocities obtained from the quiet-sun region and the coronal hole.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Dec. 15
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  • 47
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    OSO-7 results on coronal emission near 304 A (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The spectral composition and spatial distribution of equatorial coronal emission near 304 A is examined. Spectral scans indicate that the predominant line is from Si XI. Comparisons of observations with calculations of intensity changes with altitude indicate that collisional excitation is important near the sun but that photoexcitation becomes dominant beyond about 1.3 solar radii from the solar center. Observed and calculated intensities are in approximate agreement for abundances and electron densities that are within the range of observed values.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 48
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    Spatial distribution of XUV emission in solar flares (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 201; Nov. 1
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  • 49
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    Expansion of chromospheric matter in the gradual phase of solar flares (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Interferometric observations at 17 GHz of several small X-ray flares are presented along with soft X-ray observations of preflare active regions to show that a large mass increase accompanies the formation of an X-ray hot region in the corona. The total amount of energy contained in a hot coronal region is estimated, and a model is proposed in which a significant amount of the hot matter is supplied to the corona from the chromosphere during each flare. According to this model, energy produced by some coronal instability is transported by thermal conduction to the chromosphere, where dense gas is heated and subsequently expands into the corona. It is shown that impulsive heating of the chromosphere by nonthermal electrons cannot be the energy source of this model because the total energy supplied to the hot region during the gradual phase must be much greater than that supplied during the impulsive phase.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 45; Dec. 197
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  • 50
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    Monte Carlo model of the highly anisotropic solar proton event of 20 April 1971 (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 40; Feb. 197
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  • 51
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    Direct observations of a flare related coronal and solar wind disturbance (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Numerous mass ejections from the sun have been detected with orbiting coronagraphs. Here for the first time we document and discuss the direct association of a coronagraph observed mass ejection, which followed a 2B flare, with a large interplanetary shock wave disturbance observed at 1 AU. Estimates of the mass and energy content of the coronal disturbance are in reasonably good agreement with estimates of the mass and energy content of the solar wind disturbance at 1 AU. The energy estimates as well as the transit time of the disturbance are also in good agreement with numerical models of shock wave propagation in the solar wind.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 40; Feb. 197
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  • 52
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    Multispacecraft study of the solar wind velocity at interplanetary sector boundaries (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The sector structure of the interplanetary magnetic field and the solar wind velocity at the sector boundaries are compared at separations of up to 0.3 AU, 50 deg in heliocentric longitude, and 7 deg in heliographic latitude, using data from Mariner 5 en route to Venus and from the near-earth Explorer 33, 34, and 35 satellites. The polarity pattern of the magnetic sectors is found to be very similar at the two locations, and 18 pairs of corresponding sector boundaries are identified. One-hour averages of solar wind velocities near the boundaries show that the velocities near earth exceed those measured by Mariner 5 by as much as 30%. Two possible explanations of the observed velocity differences are discussed: a preferential acceleration of sector boundaries with distance, possibly caused by stream-stream interactions; and a dependence of the solar wind velocity on heliographic latitude.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; Mar. 1
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  • 53
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    The large-scale magnetic field in the solar wind (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: A large-scale, three dimensional magnetic field in the interplanetary medium with an expected classical spiral pattern to zeroth order is discussed. Systematic and random deviations which are expected are treated. The sector structure which should be evident at high latitudes is examined. Interplanetary streams are discussed as determining the patterns of magnetic field intensity. It was proposed that the large-scale spiral field can induce a meridional flow which might alter the field geometry somewhat. The nonuniformities caused by streams will probably significantly influence the motion of solar and galactic particles. It was concluded that knowledge of the 3-dimensional field and its dynamical effects can be obtained by in situ measurements by a probe which goes over the sun's poles. Diagrams of the magnetic fields are given.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-70983 , X-692-75-242
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  • 54
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    Observations of solar gamma ray continuum between 360 keV and 7 MeV on August 4, 1972 (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 55
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    Chemistry of solar material (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The calculated chemical compositions of the gaseous and condensed phases in the primitive solar nebula are presented for both equilibrium and disequilibrium condensation. The implications for the compositions of individual solar-system bodies will be briefly discussed. Condensation from an otherwise solar-composition gas in which carbon is more abundant than oxygen is mentioned.
    Keywords: SOLAR PHYSICS
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  • 56
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    The temperature structure and pressure balance of magnetic loops in active regions (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: EUV observations show many active region loops in lines formed at temperatures between 10,000 and 2,000,000 K. The brightest loops are associated with flux tubes leading to the umbrae of sunspots. It is shown that the high visibility of certain loops in transition region lines is due principally to a sharp radial decrease of temperature to chromospheric values toward the loop axis. The plasma density of these cool loops is not significantly greater than in the hot gas immediately surrounding it. Consequently, the internal gas pressure of the cool material is clearly lower. The hot material immediately surrounding the cool loops is generally denser than the external corona by a factor 3-4. When the active region is examined in coronal lines, this hot high pressure plasma shows up as loops that are generally parallel to the cool loops but significantly displaced laterally.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 57
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    A new solar carbon abundance based on non-LTE CN molecular spectra (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A detailed non-LTE analysis of solar CN spectra strongly suggest a revised carbon abundance for the sun. We recommend a value of log carbon abundance = 8.35 plus or minus 0.15 which is significantly lower than the presently accepted value of log carbon abundance = 8.55. This revision may have important consequences in astrophysics.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Nov. 15
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  • 58
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    Time-dependent 2.2-MeV and 0.5-MeV lines from solar flares (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The time dependences of the 2.2- and 0.51-MeV gamma-ray lines from solar flares are calculated, and the results are compared with observations of the 1972 August 4 and 7 flares. The time lag between the nuclear reactions and the formation of these two lines is caused by capture of the neutrons and subsequent deceleration of the positrons and decay of the radioactive nuclei. Our main results are that the calculation is consistent with the observed rise of the 2.2-MeV line on August 4, and it does not require different time dependences for the accelerated protons and high-energy electrons in the flare region. The above lags can explain the delayed gamma-ray emission observed on August 7. Positrons of energies greater than about 10 MeV could be detected in interplanetary space following large solar flares.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Dec. 1
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  • 59
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    Enrichment of heavy nuclei in He-3-rich flares (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: IMP-7 observations of five solar-flare particle events characterized by He-3 enrichment are reported which show that such events are also enriched in nuclei with charges (Z) of at least 6. The ratio of these nuclei to H-1 at approximately 3 MeV/nucleon was found to be enriched by about 10 to 100 times, while the ratio with respect to He-4 was enriched by about 3 to 30 times. It is suggested that the simultaneous enhancement of He-3 and the heavier nuclei as well as the absence of H-2 and H-3 during the observed events may be partly due to a preferential acceleration process which depends on the ratio of the square of the charge to the atomic weight of the nuclei.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 201; Oct. 15
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  • 60
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    Large-scale and solar cycle variations of the solar wind (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Space probe observations relevant to the determination of the large-scale, three-dimensional structure of the solar wind and its solar cycle variations are summarized. There is a pronounced decrease in the velocity spread about the average as distance from the sun increases (from 0.6 to 5 AU). A latitude variation is found for several plasma parameters, and a dependence on the phase of the solar activity cycle is demonstrated by some of the data.
    Keywords: SOLAR PHYSICS
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  • 61
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    High resolution observations of solar bursts at 3.7 and 11.1 cm wavelengths (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Mar. 197
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  • 62
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    Implications of observed charge states of low-energy solar cosmic rays (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Recent measurements of the charge states of low-energy (about 100 keV/nucleon) solar cosmic rays at 1 AU are discussed. The measurements are consistent with models involving charge equilibrium with neutral matter at the sun only if the particles lose about 90% of their energy owing to adiabatic deceleration in the solar wind. Such an energy loss is shown to be possible only if the diffusion coefficient for 1-MeV/nucleon particles is smaller than 100 quintillion sq cm per sec. The implications of these results for models of solar-cosmic-ray acceleration are discussed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; Apr. 1
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  • 63
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    The solar elogation distribution of low frequency radio bursts (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Over 500 days of low frequency (less than 5 MHz) radio observations from the IMP-6 spacecraft were accumulated to produce a two dimensional map (frequency versus elongation) of solar type III burst occurrences. This map indicates that most solar bursts are emitted at the second harmonic of the plasma frequency rather than the fundamental. The map also shows that the solar wind electron density varies.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-70883 , X-693-75-99
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  • 64
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    Dust in the solar nebula (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The chemical and mineralogical features of the white, Ca-rich inclusions in Allende and other carbonaceous chondrites are strikingly similar to those predicted from thermodynamic models for the highest temperature condensates from the solar nebula. Many of the physical and chemical properties of the chondritic minerals may thus be quite like those of the dust in interstellar regions. The oxygen isotopic composition of meteoritic condensates suggests that they contain a component of interstellar dust that survived the birth of the solar system.
    Keywords: SOLAR PHYSICS
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  • 65
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    The solar-flare infrared continuum (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Potential sources of infrared (1 micron to 1 mm) continuum in solar flares are considered. Several mechanisms should produce detectable fluxes: in the 350 micron window for ground-based observations, impulsive emission will arise in synchrotron radiation from 1-10 MeV electrons, and possibly thermal (free-free) continuum from the source of the white-light flare; the hot flare plasma responsible for soft X-ray emission will also emit detectable fluxes of free-free continuum in the largest flares. At shorter wavelengths the dominant infrared emission will come from the H alpha flare itself. Observations in the infrared wavelengths will help to complete the picture of flare structure in both the impulsive and gradual phases.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 66
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    A model of coronal holes (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: It has been noted that coronal holes appear to be associated with regions of diverging magnetic field in the corona. We set out to test the hypothesis that coronal holes may be caused by an increased flow of energy into the solar wind resulting directly from this diverging magnetic field pattern. Simple models were devised to approximate the energy flow down into the transition region and up into the solar wind as a function of the temperature, density, and rate of field line divergence in the corona. By assuming the rate of mechanical energy influx into the corona to be constant, it was then possible to solve numerically for the coronal temperature and density as a function of the rate of field line divergence. The results of these calculations demonstrate that a diverging field pattern can, indeed, bring about reductions in the temperature and density at the base of the corona comparable to those observed in coronal holes.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Nov. 15
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  • 67
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    The effect of intermediate-scale motions on line formation (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The problem of LTE and non-LTE line formation in the presence of nonthermal velocity fields with geometric scales between the microscopic and macroscopic limits is investigated in the cases of periodic sinusoidal and sawtooth waves. For a fixed source function (the LTE case), it is shown that time-averaged line profiles progress smoothly from the microscopic to the macroscopic limits as the geometric scale of the motions increases, that the sinusoidal motions produce symmetric time-averaged profiles, and that the sawtooth motions cause a redshift. In several idealized non-LTE cases, it is found that intermediate-scale velocity fields can significantly increase the surface source functions and line-core intensities. Calculations are made for a two-level atom in an isothermal atmosphere for a range of velocity scales and non-LTE coupling parameters and also for a two-level atom and a four-level representation of Na I line formation in the Harvard-Smithsonian Reference Atmosphere (1971) solar model. It is found that intermediate-scale velocity fields in the solar atmosphere could explain the central intensities of the Na I D lines and other strong absorption lines without invoking previously suggested high electron densities.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 202; Dec. 1
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  • 68
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    Emerging Flux Regions (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: All active regions are born as Emerging Flux Regions (EFRs) which appear in H alpha as two small plages of opposite polarity connected by parallel dark arches. After a brief review of the properties of EFRs, new observations of the birth of an EFR and apparent subsequent field reconnection are reported. Fluxrope theories are reviewed, the appearance of EFRs is predicted, and this picture is then modified on the basis of high resolution observations. One arrives at a model of this phenomenon that encompasses relevant aspects such as the axial tilt of spot groups, the observed 'rotation' of EFRs as they emerge, and the fact that EFR fluxtubes are made up of many discrete strands.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 43; Aug. 197
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  • 69
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    Semiempirical upper photosphere models - The sun /G2 V/ and Procyon /F5 IV-V/ (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A description is presented of an approach for developing a model of the average upper photosphere temperature structure of a late-type star. The approach makes use of the frequency dependence of the damping wing opacity of a strong resonance line. Difficulties related to a dependence on uncertain constant and parameter values are to be overcome with the aid of a 'calibration' relative to a solar photosphere model obtained by an independent method.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 201; Nov. 1
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  • 70
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    Solar gamma-ray lines as probes of accelerated particle directionalities in flares (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Anisotropies of charged particles accelerated in solar flares were studied by observing Doppler shifts of selected gamma-ray lines. The spectral shape was calculated of the 6.1-MeV line of O-16. If the accelerated particles are isotropic, the line remains centered at e sub 0 = 6129.4 keV, and its width (FWHM) is about 100 keV. For particle anisotropies that may be produced in solar flares, the line is shifted to lower energies by about 30 to 40 keV.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-70890 , X-660-75-96
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  • 71
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    The investigation of O and N2 densities from the OSO-7 extreme UV data (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: The results of solar radiation observations in the extreme ultra-violet spectrum from 200 A to 600 A made by the OSO-7 Satellite were studied. The results of the influence of attenuation by the atmosphere in the 250 to 500 km altitude range are presented. Using published molecular absorption cross-sections at 304 A and 256 A, the Jaccia atmospheric model is validated, and shows that a mean exospheric of 1050 K is appropriate for the sunset data.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-142759 , WOLF-00079
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  • 72
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    The triggering and subsequent development of a solar flare (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: High temporal and spatial resolution solar X-ray pictures of a flare at 1827 UT on 5 September 1973 were taken with the S-056 telescope on the Apollo telescope mount. Photographs taken at 9 sec intervals allow detailed information to be obtained about the site of the energy release, as well as about the evolution of the flare itself. Observations suggest that the flare occurred in an entire arcade of loops rather than in any single loop. Sequential brightening of different X-ray features indicates that some excitation moved perpendicular to the magnetic field of the arcade at velocities of 180 to 280 km/sec. The most intense X-ray features were located in places where the magnetic field composing the arcade had a small radius of curvature with horizontal field gradients higher than the surroundings region and where the axis of the arcade changed direction. It was felt that the arcade geometry strongly influenced the propagation of the triggering disturbance, as well as the storage and site of the subsequent deposition of energy. A magnetosonic wave is suggested as the propagating mechanism triggering instabilities that may have existed in the preflare structure.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-144228 , ATR-76(7405)-1
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  • 73
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    Theory of type 3b solar radio bursts (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: During the initial space-time evolution of an electron beam injected into the corona, the strong beam-plasma interaction occurs at the head of the beam, leading to the amplification of a quasi-monochromatic large-amplitude plasma wave that stabilizes by trapping the beam particles. Oscillation of the trapped particles in the wave troughs amplifies sideband electrostatic waves. The sidebands and the main wave subsequently decay to observable transverse electromagnetic waves through the parametric decay instability. This process gives rise to the elementary striation bursts. Owing to velocity dispersion in the beam and the density gradient of the corona, the entire process may repeat at a finite number of discrete plasma levels, producing chains of elementary bursts. All the properties of the type IIIb bursts are accounted for in the context of the theory.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-X-71060 , X-602-75-281
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  • 74
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    A search for periodic variations of solar radio emission at 3.7- and 11.1-cm wavelengths (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Periodic time variations in the emission of quiet solar regions were sought with the NRAO three-element interferometer at 3.7 and 11.1 cm. The visibility function of a source as obtained with a tracking interferometer is an implicit function of time, because of projected baseline changes, and therefore only observations taken when the baseline changes vary slowly with time were used. The visibility function shows significant time variations, but a power-spectrum analysis of the data revealed no unique periodicity.
    Keywords: SOLAR PHYSICS
    Type: Royal Astronomical Society; vol. 173
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  • 75
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    Possible new Jovian thermospheric models (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Possibilities of models for the Jovian thermosphere, based upon mechanical heating, have been explored. Under certain reasonable assumptions about the magnitude of the critical Richardson number, the correction to the conventional expression for the eddy heat flux, and the height dependence of the eddy diffusion coefficient, a very hot thermosphere could result, yielding exospheric temperatures more in tune with the bounds being suggested by the recent optical and radio occultation experiments.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 200; Sept. 15
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  • 76
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    Sheath-limited unipolar induction in the solar wind (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A model of the steady-state interaction between the solar wind and an electrically conducting body having neither an atmosphere nor an intrinsic magnetic field sufficient enough to deflect the plasma flow is presented which considers some effects of a plasma surface sheath on unipolar induction. The Sonett-Colburn (1967, 1968) unipolar dynamo model is reviewed, and it is noted that the unipolar dynamo response of an electrically conducting body in the solar wind's motional field can be controlled by sheath effects in certain cases where the body radius is less than a certain critical value. It is shown that sheath effects do not limit the unipolar response of the moon or Mercury since their body radii are much larger than their critical radii. Sheath effects are also considered for asteroids, the Martian satellites, the irregular Jovian satellites, the outer satellites of Saturn, and meteorite parent bodies in a primordial enhanced solar wind.
    Keywords: SOLAR PHYSICS
    Type: Astrophysics and Space Science; 36; Aug. 197
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  • 77
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    On the rotation of gas and magnetic fields at the solar photosphere (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: We point out that observations of a 5 percent velocity difference between photospheric gas and magnetic structures at a given latitude may simply result from angular momentum conservation by fluid elements in the convection zone. Estimates of the viscosity and magnetic drag are considered, and we conclude that they probably are not large enough to enforce strictly rigid rotation.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 1
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  • 78
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    Low-energy solar cosmic rays - A bibliography (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Reviews of Geophysics and Space Physics; 13; July 197
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  • 79
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    Automatic solar image motion measurements (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The solar seeing image motion has been monitored electronically and absolutely with a 25 cm telescope at three sites along the ridge at the southern end of the Magdalena Mountains west of Socorro, New Mexico. The uncorrelated component of the variations of the optical flux from two points at opposite limbs of the solar disk was continually monitored in 3 frequencies centered at 0.3, 3 and 30 Hz. The frequency band of maximum signal centered at 3 Hz showed the average absolute value of image motion to be somewhat less than 2sec. The observer estimates of combined blurring and image motion were well correlated with electronically measured image motion, but the observer estimates gave a factor 2 larger value.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 80
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    Sunspot motion, flares and type III bursts in McMath 11482 (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 81
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    EUV emission, filament activation and magnetic fields in a slow-rise flare (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Results are reported for observations and analysis of synoptic data on a 1B flare that occurred on January 19, 1972. The observations include large-scale H-alpha movies of the flare and pre-flare developments, OSO-7 satellite data on soft X-ray and EUV developments, magnetograms, and hard X-ray observations. Theoretical force-free magnetic field configurations are compared with structures seen in the soft X-ray, EUV, and H-alpha images, and the evolution of the flare is described. The energy available for the flare is estimated from the change of magnetic field inferred from the H-alpha filtergrams and from force-free field calculations. It is suggested that the flare originated in a twisted filament where it was compressed by emerging fields, and it is shown that the flare started below the corona and appeared to derive its energy from the magnetic fields in or near the filament.
    Keywords: SOLAR PHYSICS
    Type: AD-A050171 , AFGL-TR-76-0021 , Solar Physics; 41; Apr. 197
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  • 82
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    The solar flare iron line to continuum ratio and the coronal abundances of iron and helium (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Narrow band Ross filter measurements of the Fe 25 line flux around 0.185 nm and simultaneous broadband measurements during a solar flare were used to determine the relationship between the solar coronal abundances of iron and helium. The Fe 25 ion population was also determined as a function of time. The proportional counter and the Ross filter on OSO-7 were utilized. The data were analyzed under the separate assumptions that (1) the electron density was high enough that a single temperature could characterize the continuum spectrum and the ionization equilibrium, and that (2) the electron density was low so that the ion populations trailed the electron temperature in time. It was found that the density was at least 5x10 to the 9th power, and that the high density assumption was valid. It was also found that the iron abundance is 0.000011 for a helium abundance of 0.2, relative to hydrogen.
    Keywords: SOLAR PHYSICS
    Type: NASA-CR-146358 , ATR-75(7464)-1
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  • 83
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    Solar flux and its variations (1975)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: Data are presented on the solar irradiance as derived from a number of sources. An attempt was made to bring these data onto a uniform scale. Summation of fluxes at all wavelengths yields a figure of 1357.826 for the solar constant. Estimates are made of the solar flux variations due to flares, active regions (slowly varying component), 27-day period, and the 11-yr cycle. Solar activity does not produce a significant variation in the value of the solar constant. Variations in the X-ray and EUV portions of the solar flux may be several orders of magnitude during solar activity, especially at times of major flares. It is established that these short wavelength flux enhancements cause significant changes in the terrestrial ionosphere.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Possible Relationships between Solar Activity and Meteorol. Phenomena; p 97-117
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  • 84
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    Decameter storm radiation. I (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A description is given of the evolution of six decametric storms which took place during the period from January to August, 1971. The storms described were observed with a swept frequency interferometer. The array consists of sixteen log-periodic antennas, equally spaced on a two mile east-west baseline. The association of storms with optical activity and photospheric fields is considered along with the relation of decametric storms to coronal magnetic fields and the association of storms with decimeter and meter wavelength activity. It is shown that decametric storms are always associated with storms at the meter and decimeter wavelengths.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 85
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    Evidence for downflow following a coronal transient (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: On 11 September 1973 a peculiar prominence was observed. The prominence displayed strong (approximately 50 km per sec) systematic motions toward and away from the observer. The unusual spectrographic appearance of the prominence might have been due to downflowing material lifted into the corona during an earlier coronal transient.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 86
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    Slow X-ray bursts and flares with filament disruption (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The data from OGO-5 and OSO-7 X-ray experiments have been compared with optical data from six chromospheric flares with filament disruption associated with slow thermal X-ray bursts. Filament activation accompanied by a slight X-ray enhancement precedes the first evidence of H-alpha flare by a few minutes. Rapid increase of the soft X-ray flux accompanies the phase of fastest expansion of the filament. Plateau or slow decay phases in the X-ray flux are associated with slowing and termination of filament expansion. The soft X-ray flux increases as F approaches (A + Bh)h, where h is the height of the disrupted prominence at any given time and A and B are constants. We suggest that the soft X-ray emission originates from a growing shell of roughly constant thickness of high-temperature plasma due to the compression of the coronal gas by the expanding prominence.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 87
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    Temperature variation with latitude in the upper solar photosphere - Relevance to solar oblateness measurements and facular models (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 88
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    Flare model chromospheres and photospheres (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Homogeneous plane-parallel model atmospheres for solar flares have been constructed to approximately simulate observations of flares. The wings of the Ca II lines have been used to derive flare upper photosphere models, which indicate temperature increases of about 100 K over the temperature distribution in the pre-existing facula at a height of 300 km. In the case of flares covering sunspots the temperature rise seems to occur much higher in the atmosphere. We find that with increasing flare importance the heights of the upper chromosphere and transition region occur lower in the solar atmosphere, accounting for the factor of 60-600 increase in pressure in these regions relative to the quiet sun. The Ca II line profiles agree with observations only by assuming a macrovelocity distribution that increases with height. Also, the chromospheric parts of flares appear to be highly inhomogeneous. We show that shock and particle heated flare models do not agree with the observations and propose a thermal response model for flares. In particular, it appears that heating in the photosphere is an essential aspect of flares.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; June 197
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  • 89
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    Unusual emission of iron nuclei from the sun (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Sustained emission of low-energy solar particles with a composition richer in iron than oxygen has been observed during the time period May 7-17, 1974. Between 0.7 and 4 MeV per nucleon the relative abundances of C:O:Fe are 0.65:1:1.35. We suggest that these observations provide an indication of the effects of heavy-ion enrichment in the lower corona of the sun.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 200; Aug. 15
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  • 90
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    Resonance line transfer with partial redistribution. IV - A generalized formulation for lines with common upper states. V - The solar Ca II lines (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A generalized formulation is given for treating partial redistribution effects in transfer problems in resonance lines with common upper states. The formulation allows explicitly for the possibility that several spectral lines may arise in transitions from a given upper level to several sharp lower levels, including, for example, the ground state and metastable states. Line profiles for the Ca II H and K lines have been calculated, accounting for the partial frequency coherence of scattered photons. These profiles are compared with calculations made with identical atomic and atmospheric models but assuming complete redistribution. Very significant differences between the profiles obtained using these two different physical descriptions of the scattering process are found, and it is now apparent that the assumption of complete redistribution is a serious oversimplification of the actual physical situation. The results question the validity of equating brightness temperatures observed at K(sub 1) in stellar spectra with minimum temperatures in stellar chromospheres; it appears likely that such a procedure will systematically underestimate the value of T-min.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; Aug. 1
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  • 91
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    Angular distributions of solar protons and electrons (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: High angular-resolution measurements of directional fluxes of solar particles in space have been obtained with detectors aboard OGO-5 during the cosmic ray event of Nov. 18, 1968. This is the only case on record for which sharply-defined directional observations of protons and electrons covering a wide rigidity range (0.3 MV to 1.5 GV) are available. The satellite experiment provided data for determining pitch-angle distributions with respect to the direction of the local interplanetary magnetic field lines during the lengthy highly anisotropic phase of the event. The results have been interpreted in the light of the temporal flux profiles and the state of the interplanetary medium.
    Keywords: SOLAR PHYSICS
    Type: Planetary and Space Science; 23; Aug. 197
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  • 92
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    Morphological evolution of X-ray flare structures from the rise through the decay phase (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The morphological evolution of 12 solar X-ray subflares from onset through the decay phase has been studied using photographic X-ray images obtained from Skylab. The spatial configurations are found to vary widely from flare to flare, but they appear to be composed of two basic kinds of structures. The first, termed 'X-ray kernels', are brightest during the rise phase; the second, looplike structures, appear during the maximum and decay phases of the event. The X-ray kernels are small pointlike structures which may be related to the nonthermal phases of flares.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 1
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  • 93
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    The helium chromosphere, coronal holes, and stellar X-rays (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The solar chromosphere at the limb seen in D3 is an irregular bright band 1000 km thick with a dark band 1000 km thick beneath. The D3 chromosphere disappears in coronal holes. It is shown that the D3 emission, as well as the other He I and He II lines, can be explained quantitatively by photoionization by coronal back-radiation. A Chapman layer with N(He)H = 5 times 10 to the 17th power is formed near tau = 1 in the He I and He II continua. The chromospheric He emission or absorption is weak in coronal holes because there is no coronal back-radiation. Based on this model, the soft X-ray flux from stars with He 10830-A absorption lines is estimated as proportional to the 10830-A equivalent width and the apparent area.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 199; July 1
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  • 94
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    Broad-band circular polarization of sunspots - Spectral dependence and theory (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 41; 2, Ju; June 197
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  • 95
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    The behaviour of minor species in the solar wind (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The flow of minor species in the solar wind is considered on the basis of a model in which all species are heated in an arbitrary manner as they leave the sun and the minor species interact with the background proton-electron plasma through the radial electric field associated with the latter and by means of Coulomb collisions. In order to produce satisfactory results in which the ions all move at more or less the same speed at the orbit of the earth, it is necessary to introduce heating functions such that each species is given energy in proportion to its mass. Coulomb collisions are found to be important as a means of removing energy from the heavier species close to the sun and bringing all species closer to thermal equilibrium at great distances from the sun. Substantial velocity differences can occur between species, especially close to the sun. Furthermore it is not difficult to construct solutions in which the bulk velocity of the helium ions exceeds that of the solar wind, as is often observed.
    Keywords: SOLAR PHYSICS
    Type: Zeitschrift fuer Geophysik; 41; 3, 19; 1975
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  • 96
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    Measurements of solar magnetic fields by Fourier transform techniques. I - Unsaturated lines (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: If the basic profile shapes of the normal Zeeman triplet do not have zeros in their Fourier transform, the magnetic field splitting can be determined independent of the profile shape. When the ratio of the splitting of the components is greater than the intrinsic FWHM of the component profiles, the magnetic splitting can be determined with significantly greater accuracy than the measurement accuracy of the original profile. For Gaussian shaped components and a ratio of magnetic splitting to FWHM of 1.5, the noise reduction factor is 25.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 97
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    The large coronal transient of 10 June 1973. I - Observational description (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Ground-based and Skylab coronagraph observations are used to trace a coronal loop transient from its inception near the surface to a distance of 5 solar radii. Events in the lower solar atmosphere associated with this feature are outlined chronologically, and its physical appearance is described. The densities, mass, and energy of the transient are estimated, its shape is determined, and its typical and atypical characteristics are noted. It is inferred that this transient was caused by the emergence of an active region. It is shown that it was not immediately preceded by a flare and that the material at its leading edge did not decelerate appreciably, even at approximately 5 solar radii.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 42; May 1975
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  • 98
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    Long-term evolution of solar sector structure (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The large-scale structure of the solar magnetic field during the past five sunspot cycles (representing by implication a much longer interval of time) has been investigated, using the polarity (toward or away from the Sun) of the interplanetary magnetic field as inferred from polar geomagnetic observations. The polarity of the interplanetary magnetic field has previously been shown to be closely related to the polarity (into or out of the Sun) of the large-scale solar magnetic field. It appears that a solar structure with four sectors per rotation persisted through the past five sunspot cycles with a synodic rotation period near 27.0 days, and a small relative westward drift during the first half of each sunspot cycle and a relative eastward drift during the second half of each cycle. Superimposed on this four-sector structure there is another structure with inward field polarity, a width in solar longitude of about 100 deg, and a synodic rotation period of about 28 to 29 days. This 28.5-day structure is usually most prominent during a few years near sunspot maximum. Some preliminary comparisons of these observed solar structures with theoretical considerations are given.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 99
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    Dynamic response of an isothermal static corona to finite-amplitude disturbances (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 41; Apr. 197
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  • 100
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    Solar cosmic ray 'square wave' of August 1972 (1975)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Three Rice University suprathermal ion detector experiments (sides) were deployed on the lunar surface during the Apollo 12, 14, and 15 missions. During the exceptional period of solar activity in August 1972, penetrating particles were observed by all side detectors on the night side of the moon. The penetrating particles are tentatively identified as solar protons with energies (approximately 25 MeV or greater) that were able to penetrate the shielding of all detectors. Of particular interest is the occurrence on August 5 of a 'square wave' flux enhancement of 2-hour duration. Data from a variety of ground-based and space experiments are examined in relation to the square wave. Based on the results of this investigation a model relating the square wave to the flare plasma propagation is proposed. This model hypothesizes transport of energetic particles along a 'corridor' formed by the tangential discontinuity produced by the driver gas of a flare-induced shock wave. This model could explain other frequently observed delayed particle events.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 80; May 1
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