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  • Other Sources  (310)
  • SOLAR PHYSICS  (310)
  • 1980-1984  (310)
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  • 1983  (310)
  • 1
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    Report on the Workshop on Intercomparison of Solar UV Irradiance Measurements and Related Instrument Calibration (1983)
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    Publication Date: 2011-08-19
    Description: The knowledge of the absolute value of the solar ultraviolet irradiance did not improve very much during the rising phase of the solar cycle 21. The variations associated with the solar rotation period were observed by means of three satellites, namely, the Atmospheric Explorer E (AE-E), Nimbus 7 and the Solar Mesospheric Explorer (SME). Long-term variations related to the solar activity cycle are not well known. Values were deduced during the solar cycle 21 from the AE-E satellite and the rocket program performed by the Laboratory for Atmospheric and Space Physics leading to variations of about a factor of 2 around 150 nm but definitely less than 20 percent beyond 175 nm. Such low level of variation is still masked by the current uncertainties and reproducibility of the observations performed since 1976. The uncertainties of recent observations are reported with their discrepancies. The gaps between the current accuracy goals and the achievements are still very important. The challenge for the next three years is to improve both the accuracy and the precision of future observations at the level of the available irradiance standards and to measure quantitatively long-term variations of the order of a few percent. The main causes of these gaps are identified.
    Keywords: SOLAR PHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program. Handbook for MAP, Vol. 8; p 45-51
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  • 2
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    Electrodynamic coupling in magnetically confined stellar X-ray loops (1983)
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    Publication Date: 2011-08-18
    Description: The solar coronal complex X-ray structure is now known to involve radiation loops that coincide spatially with the magnetic loops confining the radiating plasma. An effort is presently made to identify primary submodels involved in the global coupling between a mechanical energy reservoir of beta value greater than 1 and a contiguous site of X-ray activity whose beta value is lower than 1. The 'dynamo' model invoked establishes a quantitative connection between mechanical driver properties and the dimensions, field strength, and number density distribution of elemental magnetic loops.
    Keywords: SOLAR PHYSICS
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  • 3
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    Interpretation of vector magnetograph data including magneto-optic effects. I - Azimuth angle of the transverse field (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In this paper, the presence of Faraday rotation in measurements of the orientation of a sunspot's transverse magnetic field is investigated. Using observations obtained with the Marshall Space Flight Center's (MSFC) vector magnetograph, the derived vector magnetic field of a simple, symmetric sunspot is used to calculate the degree of Faraday rotation in the azimuth of the transverse field as a function of wavelength from analytical expressions for the Stokes parameters. These results are then compared with the observed rotation of the field's azimuth which is derived from observations at different wavelengths within the Fe I 5250 A spectral line. From these comparisons, it is found: the observed rotation of the azimuth is simulated to a reasonable degree by the theoretical formulations if the line-formation parameter is varied over the sunspot; these variations are substantiated by the line-intensity data; for the MSFC system, Faraday rotation can be neglected for field strengths less than 1800 G and field inclinations greater than 45 deg; to minimize the effects of Faraday rotation in sunspot umbrae, MSFC magnetograph measurements must be made in the far wings of the Zeeman-sensitive spectral line.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 88; 51-64
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  • 4
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    Dynamics of a surge observed in the C IV and H alpha lines (1983)
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    Publication Date: 2011-08-18
    Description: Time sequences of a surge have been obtained in Active Region 2701 during a coordinated SMY program, on October 2nd, 1980, while the MSDP spectrograph operated in H-alpha at the Meudon Solar Tower and the UVSP spectrometer on SMM observed in the 1548 A C IV resonance line. The cold (H-alpha) and hot (C IV) material follow the same channel, and the event lasts about 10 min in both lines. A good correlation is found between H-alpha and C IV velocities; radial velocities along the surge are in the range 40-60 km/s in both cases. The observations are consistent with the hypothesis that a pressure gradient drives the surge. The H-alpha data seem to indicate the presence of a shock wave in the chromosphere, while the C IV quantities (velocities, accelerations) vary on a very short time scale. Their maxima occur at some locations which could be interpreted as 'pinched' zones.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 127; 2, No; 337-344
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  • 5
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    Differences in the temporal variations of solar UV flux, 10.7-cm solar radio flux, sunspot number, and Ca-K plage data caused by solar rotation and active region evolution (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Attention is given to two types of temporal variations in the solar UV spectral irradiance caused by solar rotation and active region evolution. It is noted that the first type of dissimilar temporal behavior occurs when concentrations of solar active regions evolve at solar longitudes nearly 180 deg apart. Both the UV observations and modeled UV fluxes based on Ca-K plage data then exhibit pronounced 13-day periodicity, whereas the 10.7-cm solar radio flux and sunspot number exhibit quite dissimilar temporal variations. This type of dissimilarity is related to the modeled UV flux and has a dependence on the solar central meridian distance that is narrower than that for the 10.7-cm radio flux or for sunspot numbers. A second case of marked dissimilarity is seen when major new solar active regions arise and dominate the full-disk fluxes for several rotations. It is found that the strongest peaks in 10.7 cm and sunspot numbers tend to occur on their first rotation, for example, during major dips in the total solar irradiance, whereas the Ca-K plages and UV enhancements peak on the next rotation and then decay more slowly on subsequent rotations.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9883-988
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  • 6
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    The stability of coronal loops - Finite-length and pressure-profile limits (1983)
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    Publication Date: 2011-08-18
    Description: Results are described from a quickly converging, necessary-and-sufficient, MHD-stability test for coronal-loop models. The primary stabilizing influence arises from magnetic line tying at the photosphere, and this end conditions requires a series expansion of possible loop excitations. The stability boundary is shown to quickly approach a limit as the number of terms increases, providing a critical length for the loop in proportion to its transverse magnetic scale. Several models of force-free-field profiles are tested and the stability behavior of a localized current channel, embedded in an external current-free region, is shown to be superior to that of other, broader, current profiles. Pressure-gradient effects, leading to increased or decreased stability, are shown to be amplified by line tying. Long loops must either conduct low net current, or exhibit an axial-field reversal coexisting with a low-pressure core. The limits on stability depend on the magnetic aspect ratio, the plasma-to-magnetic pressure ratio, and the field orientation at the loop edge. Applications of these results to the structure of coronal loops are described.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 88; 163-177
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  • 7
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    Implications of high-energy neutron observations from solar flares (1983)
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    Publication Date: 2011-08-18
    Description: The time-dependent flux of high-energy neutrons discovered from the solar flare of 1980 June 21 provides a new technique for determining the total number and energy spectrum of accelerated protons and nuclei at the sun. The implications of these observations on gamma-ray emission, relativistic electron spectrum and number, proton and electron energy contents, and the location of the interaction region are also examined.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 273; L41-L45
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  • 8
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    Fluid motions in the solar chromosphere-corona transition region. IV - Mass motions over sunspot umbrae (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 273; 374-380
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  • 9
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    Solar irradiance variations. II - Analysis of the extreme ultraviolet measurements onboard the Atmosphere Explorer E satellite (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Five of the extreme ultraviolet channels (L-alpha, L-beta, He I, He II, Fe XV) measuring irradiance fluctuations on board the AE-E satellite between 1977 and 1980 have been studied in detail. It is shown that the daily variations correspond very closely to the daily variations in solar radio emission (F10.7), but that the UV data are afflicted with serious and to date unrecognized calibration changes during the period of operation of the instruments. In order to correct for these changes, a statistical analysis is carried out, and a set of corrections to the raw data is suggested. The resulting, now uniform, data are then compared with rocket measurements (L-alpha) and data acquired onboard the AE-C satellite (L-beta). Finally the remaining discrepancies are discussed. After concluding that they are below the overall level of uncertainties, a first-order 10-year run of EUV irradiances derived from F10.7 data is proposed. This estimate includes the ratio of irradiance levels between the maxima of solar cycles 20 and 21 and the intervening minimum.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9037-905
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  • 10
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    Determining the solar wind speed above active regions using remote radio-wave observations (1983)
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    Publication Date: 2011-08-18
    Description: A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.
    Keywords: SOLAR PHYSICS
    Type: Science (ISSN 0036-8075); 222; 506-508
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  • 11
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    Hydromagnetic waves, turbulence, and collisionless processes in the interplanetary medium (1983)
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    Publication Date: 2011-08-18
    Description: An extended discussion is conducted concerning the origin and evolution of interplanetary hydromagnetic waves and turbulence, and their influence on the large scale dynamics of the solar wind. The solar wind is at present the preeminent medium for the study of hydromagnetic waves and turbulence, providing an opportunity for advancement of understanding of the most fundamental processes of the astrophysical plasmas. All interplanetary fluctuations whose time scale is observed to be greater than 1 sec can be regarded as hydromagnetic fluctuations. It has been found to be simplest, and generally very satisfactory, to model interplanetary variations as fluctuations in an MHD fluid. Attention is given to the classification of wave modes, geometrical hydromagnetics, Alfven wave pressure, rugged invariants, and the kinetic theory of collisionless processes.
    Keywords: SOLAR PHYSICS
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  • 12
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    Behavior of transition-region lines during impulsive solar flares (1983)
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    Publication Date: 2011-08-18
    Description: The emissions observed in lines originating in the transition-region plasma, particularly during impulsive flares, are investigated using data collected by the Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission. Data concerning lines from ions such as Si II, C IV, Si IV, O V, and Fe XXI are analyzed. Topics examined include the transition region away from sunspots, oscillatory motions above sunspots, the shape of the transition region, the transition region during flares, and O V and Fe XXI during flare flash phases.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0038-0938)
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  • 13
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    Gamma-ray lines and neutrons from solar flares (1983)
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    Publication Date: 2011-08-18
    Description: The energy spectrum of accelerated protons and nuclei at the site of a limb flare was derived by a technique, using observations of the time dependent flux of high energy neutrons at the earth. This energy spectrum is very similar to the energy spectra of 7 disk flares for which the accelerated particle spectra was previously derived using observations of 4 to 7 MeV to 2.223 MeV fluence ratios. The implied spectra for all of these flares are too steep to produce any significant amount of radiation from pi meson decay. It is suggested that the observed 10 MeV gamma rays from the flare are bremsstrahlung of relativistic electrons. Previously announced in STAR as N83-19695
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0038-0938)
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  • 14
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    A comparison of coronal and interplanetary current sheet inclinations (1983)
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    Publication Date: 2011-08-18
    Description: The HAO white light K-coronameter observations show that the inclination of the heliospheric current sheet at the base of the corona can be both large (nearly vertical with respect to the solar equator) or small during Cararington rotations 1660 - 1666 and even on a single solar rotation. Voyager 1 and 2 magnetic field observations of crossing of the heliospheric current sheet at distances from the sun of 1.4 and 2.8 AU. Two cases are considered, one in which the corresponding coronameter data indicate a nearly vertical (north-south) current sheet and another in which a nearly horizontal, near equatorial current sheet is indicated. For the crossings of the vertical current sheet, a variance analysis based on hour averages of the magnetic field data gave a minimum variance direction consistent with a steep inclination. The horizontal current sheet was observed by Voyager as a region of mixed polarity and low speeds lasting several days, consistent with multiple crossings of a horizontal but irregular and fluctuating current sheet at 1.4 AU. However, variance analysis of individual current sheet crossings in this interval using 1.92 see averages did not give minimum variance directions consistent with a horizontal current sheet. Previously announced in STAR as N83-31566
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 1
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  • 15
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    The solar O III spectrum. II - Longer wavelengths, line widths, and the He II Lyman alpha radiation field (1983)
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    Publication Date: 2011-08-18
    Description: The solar O III spectrum above 900 A is analyzed, including several visible and infrared lines which are important in nebular studies. The dependence of the line intensities on the rate of photoexcitation by He Ly-alpha is determined, and the observability of these lines in the solar spectrum is studied. The impact approximation is employed to calculate the expected line widths of the stronger solar O III lines. The photoexciting field at 304 A calculated from the observed intensities of the O III lines below 900 A (Bhatia et al., 1982) is compared with the field predicted by a recent model (Avrett et al., 1976). It is shown that additional radiation trapping must be present beyond that given by this model.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 53; Sept
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  • 16
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    Measurements on a shock wave generated by a solar flare (1983)
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    Publication Date: 2011-08-18
    Description: It is shown that path-integrated radio-scattering measurements of the solar wind velocity yield higher estimates than those of point measurements. The post-shock speed is determined from radio scattering measurements by selection of the maximum of the radio-scattering deduced from the velocity-time curve, whereas velocity points on the rising edge of the shock underestimate the post-shock gas velocity, and therefore the shock speed. However, it is suggested that large uncertainties reside in using radio techniques for measurements of parameters of the shock wave, and the uncertainties may be large enough to encompass the lower velocity values calculated by a point method of measurement.
    Keywords: SOLAR PHYSICS
    Type: Nature (ISSN 0028-0836); 304; Aug. 25
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  • 17
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    Solar radius change between 1925 and 1979 (1983)
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    Publication Date: 2011-08-18
    Description: From an analysis of numerous reports from different locations on the duration of totality of the solar eclipses on January 24, 1925, and February 26, 1979, it is found that the solar radius at the earlier date was 0.5 arcsec (or 375 km) larger than at the later date. The correction to the standard solar radius found for each eclipse is different when different subsets of the observations are used (for example, edge of path of totality timings compared with central timings). This is seen as suggesting the existence of systematic inaccuracies in our knowledge of the lunar figure. The differences between the corrections for both eclipses, however, are very similar for all subsets considered, indicating that changes of the solar size may be reliably inferred despite the existence of the lunar figure errors so long as there is proper consideration of the distribution of the observations. These results are regarded as strong evidence in support of the occurrence of solar radius changes on shorter than evolutionary time scales.
    Keywords: SOLAR PHYSICS
    Type: Nature (ISSN 0028-0836); 304; Aug. 11
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  • 18
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    Solar oscillations with 13-day period (1983)
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    Publication Date: 2011-08-18
    Description: Reference is made to the solar observations made by Claverie et al. (1982) over a three-month period in the summer of 1981 which show oscillatory velocity with a period of 13.1 days and amplitude of 6.6 m/s. These investigators reject the possibility that they see the Doppler shift from a radial oscillation, because the amplitude is implausibly large. They also do not believe that their signal was induced by solar magnetic fields, since typical mean solar fields are too small. Photo-electric drift-scan measurements of the solar diameter and full-disk magnetograms taken at Kitt Peak National Observatory are examined here for evidence of variations corresponding to the velocity oscillations of the 13.1-day period. An upper limit on radius variations is reported which is a factor of six below the amplitude needed to explain the velocity observations as a radial oscillation. Attention is also given to the possible role of the rotation of large-scale surface magnetic features.
    Keywords: SOLAR PHYSICS
    Type: Nature (ISSN 0028-0836); 304; Aug. 11
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  • 19
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    Formation of the Cl I line at 1351 A in the solar chromosphere (1983)
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    Publication Date: 2011-08-18
    Description: The formation of the multiplet containing the Cl I 1351 A line is investigated due to the unusual brightness of this line. It is determined that this line is formed via a fluorescence effect driven by the 1335 A line of C II. Non-LTE calculations including this effect are found to agree with the observed line intensity. It is shown that the 1347 and 1363 A lines of Cl I do not benefit from this effect and they are predicted to be approximately 100 times weaker.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 266
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  • 20
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    Observations of solar oscillations of low and intermediate degree (1983)
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    Publication Date: 2011-08-18
    Description: Measurements are presented of solar velocity oscillations with spherical harmonic degree 1-139 and angular order approximately 0. With an amplitude sensitivity of approximately 2 cm/s, trapped acoustic wave modes of radial orders 2-26 are observed at frequencies between 1.7 and 5.5 mHz. The radial order identifications of low-degree modes previously inferred from theory are confirmed. Only marginal evidence of long-period, gravity-mode oscillations is found.
    Keywords: SOLAR PHYSICS
    Type: Nature; 302; Mar. 3
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  • 21
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    Magnetic canopies in unipolar regions (1983)
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    Publication Date: 2011-08-18
    Description: Base-height statistics are presented for magnetic canopies in six unipolar magnetic regions which were observed near the limb with the Kitt Peak Vacuum Telescope and Diode Array Magnetograph during the period 25 April-3 July, 1980. As in earlier studies, extensive areas are found to be covered by low-lying canopies.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 87; Aug. 198
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  • 22
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    Corotating pressure waves without fast streams in the solar wind (1983)
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    Publication Date: 2011-08-18
    Description: Voyager 1 and 2 magnetic field and plasma data are presented which demonstrate the existence of large scale, corotating, non-linear pressure waves between 2 AU and 4 AU that are not accompanied by fast streams. The pressure waves are presumed to be generated by corotating streams near the sun. For two of the three pressure waves that are discussed, the absence of a stream is probably a real, physical effect, viz., a consequence of deceleration of the stream by the associated compression wave. For the third pressure wave, the apparent absence of a stream may be a geometrical effect; it is likely that the stream was at latitudes just above those of the spacecraft, while the associated shocks and compression wave extended over a broader range of latitudes so that they could be observed by the spacecraft. It is suggested that the development of large-scale non-linear pressure waves at the expense of the kinetic energy of streams produces a qualitative change in the solar wind in the outer heliosphere. Within a few AU the quasi-stationary solar wind structure is determined by corotating streams whose structure is determined by the boundary conditions near the sun. Previously announced in STAR as N83-19694
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Aug. 1
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  • 23
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    Microwave and hard X-ray observations of a solar flare with a time resolution better than 100 ms (1983)
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    Publication Date: 2011-08-18
    Description: Simultaneous microwave and X-ray observations are presented for a solar flare detected on 1980 May 8 starting at 1937 UT. The X-ray observations were made with the Hard X-ray Burst Spectrometer on the Solar Maximum Mission and covered the energy range from 28-490 keV with a time resolution of 10 ms. The microwave observations were made with the 5 and 45 foot antennas at the Itapetinga Radio Obervatory at frequencies of 7 and 22 GHz, with time resolutions of 100 ms and 1 ms respectively. Detailed correlation analysis of the different time profiles of the event show that the major impulsive in the X-ray flux preceded the corresponding microwave peaks at 22 GHz by about 240 ms. For this particular burst the 22 GHz peaks preceded the 7 GHz by about 1.5s. Observed delays of the microwave peaks are too large for a simple electron beam model but they can be reconciled with the speeds of shock waves in a thermal model. Previously announced in STAR as N82-30215
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 84; April 19
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  • 24
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    The isotopic composition of solar flare noble gases (1983)
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    Publication Date: 2011-08-18
    Description: The relative elemental and isotopic abundances of noble gases provide insights into a number of topics related to the solar system. Neon is in many ways the most diagnostic of the noble gases. The diagnostic character is mainly related to the variation in the relative abundance of the two most abundant neon isotopes, Ne-20 and Ne-22. The available evidence suggests that trapped neon found in meteorites and in lunar samples consists of as many as five isotopically distinct components, including neon A, B, C, D, and E. Neon B has been shown to be due to solar wind neon which has been directly implanted into the material found in a meteorite. It appears that neon E is extrasolar in origin. There exist ambiguities regarding the origins of the remaining three components. The present investigation is concerned with a reexamination of the existing data in an effort to eliminate or at least clarify these ambiguities. It is found that neon C is apparently due to directly implanted, low-energy solar flare neon nuclei.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 266
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  • 25
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    The rotational spectrum of g-modes in the sun (1983)
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    Publication Date: 2011-08-18
    Description: Observations and calculations are presented which strongly suggest that the unique sequence of rotation rates due to g-modes is active in the sun. It is found that all angular harmonics from 1 = 2-11 appear to be resolved, while higher harmonics up to at least 1 = 20 also seem to be active. The extreme narrowness of many of the spectral lines indicates that the g-modes are locked in sets of constant 1 by a local mechanism which excites the modes and possibly regulates the long-term precision of their rotation. These sets act as a system of resonant, or nearly resonant, clocks which impose a degree of periodicity upon solar activity and measure the mean solar interior rotation
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 264
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  • 26
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    Observation of chromospheric evaporation during the Solar Maximum Mission (1983)
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    Publication Date: 2011-08-18
    Description: A study is presented of the upward motions of part of the soft X-ray emitting plasma using data for flares collected in 1980 by the Bent Crystal Spectrometer and the Hard X-ray Burst Spectrometer on the Solar Maximum Mission satellite. Results show that upward motions of the soft X-ray plasma are temporally associated with the build up of the thermal phase of flares and with the period of energy deposition as indicated by the hard X-ray emission. In addition, it is found that the hardness of the hard X-ray spectrum, the evaporation velocity, and the rate of increase of the gradual phase are correlated. It is also possible that the total electron energy deposited in the chromosphere, the peak emission measure of the evaporating plasma, and the peak emission measure of the thermal coronal plasma may also be correlated.
    Keywords: SOLAR PHYSICS
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  • 27
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    Conductive flux in the chromosphere derived from line linear polarization observation (1983)
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    Publication Date: 2011-08-18
    Description: It is shown that quantitative information on the mechanisms of energy transport which take place in solar flares can be obtained by measurement of impact line polarization. Linear polarization in two chromospheric lines (H-alpha and SI 1437 A) observed in the gradual phase of solar flares was investigated. The polarized electric vector is shown to be directed towards the center of the disk. The relationship between conductive heat flux and linear line polarization is determined using a function which represents the velocity distribution of electrons carrying heat flux. The relationship between linear polarization and heat flux is applied to the observed degree of polarization, which yields the conductive heat flux in the high chromosphere. It is determined that this conductive flux is of the order of magnitude of the total radiation loss in the chromosphere and below, which is also of the order of magnitude of the conductive flux in the transition zone.
    Keywords: SOLAR PHYSICS
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  • 28
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    Radio blips and hard X-rays in solar flares (1983)
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    Publication Date: 2011-08-18
    Description: The properties of short, narrow-band spikes occurring in groups at decimetric wavelengths have been extensively analyzed. The bursts, termed blips in the literature, have been found to appear in the impulsive phase of flares. They are associated with hard X-ray emission in 40 percent of all cases with simultaneous coverage. The correspondence between blips and X-ray spikes is generally not one-to-one, blips being more numerous than X-ray spikes. In some cases, however, close correlations between single events have been found. Blips have been discovered to drift in frequency and to decay in time similarly to type III bursts at lower frequency. They also resemble type III bursts in polarization. An analysis of starting frequencies, however, clearly shows that blips and type III bursts belong to different statistical populations. The narrow bandwidth of blips, the major qualitative difference with respect to type III bursts, suggests that blips are the signature of electron beams which either decay rapidly or have a locally enhanced emission due to the presence of some low-frequency wave. Blips have been shown to be an impulsive phase phenomenon occurring at densities of one to three billion per cu cm in the low corona.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 271; Aug. 1
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    Physical conditions in a quiescent prominence derived from UV spectra obtained with the UVSP instrument on the SMM (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A quiescent prominence observed above the north-west limb on November 20, 1980, is analyzed using data obtained with the UV spectrometer and polarimeter (UVSP) on the Solar Maximum Mission (SMM). The spectral data include the lines 1215 A of H1, 1401 A of OIV, 1402 A of SIIV, 1548 A of CIV, 1640 A of HeI, and 1655 A of CI. From an analysis of these lines and their emission patterns, the physical characteristics of the prominence plasma are deduced, and it is suggested that the prominence consisted of flux tubes at various temperatures. In the hotter parts of the plasma the number density reached values of about 3 x 10 to the 11th/cu cm.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 84; April 19
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    Vertical gradients of sunspot magnetic fields (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of a Solar Maximum Mission (SMM) guest investigation to determine the vertical gradients of sunspot magnetic fields for the first time from coordinated observations of photospheric and transition-region fields are described. Descriptions are given of both the photospheric vector field of a sunspot, derived from observations using the NASA Marshall Space Flight Center vector magnetograph, and of the line-of-sight component in the transition region, obtained from the SMM Ultraviolet Spectrometer and Polarimeter instrument. On the basis of these data, vertical gradients of the line-of-sight magnetic field component are calculated using three methods. It is found that the vertical gradient of Bz is lower than values from previous studies and that the transition-region field occurs at a height of approximately 4000-6000 km above the photosphere.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 84; April 19
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    Dynamics and spectroscopy of asymmetrically heated coronal loops (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Numerical models of steady flows along coronal magnetic flux tubes of varying cross sectional areas are investigated. The flows are induced by altering the spatial symmetry of the heating. In two cases the flux tube geometry is symmetric about the top of the loop, but the spatial dependence of the heating rate is changed from a symmetric deposition which supports a stationary equilibrium to a time-independent asymmetric deposition. In a third case the volumetric heating rate is uniform, but one half of the loop is larger in volume than the other. The resulting velocity structure varies significantly with changes in the flux tube geometry. Calculations of the ionization balance and line emission for a number of ionization stages of oxygen suggest that heating induced flows may be responsible for the redshifts seen in spectral lines formed in the network at transition region temperatures.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 267
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  • 32
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    Microwave signatures from a reconnecting plasma pinch, with application to loop flares (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A calculation is made of microwave signature of a cylindrical plasma pinch undergoing magnetic reconnection, a process which occurs in many astrophysical situations, such as solar flares. Depending on the viewing angle and the average energy of the accelerated electrons, the microwaves from this betatron-like source show various amounts of circular polarization. The degree of polarization is shown to be frequency dependent, and the sense of polarization is sometimes reversed. The power spectrum is predicted to have several interesting properties, which can be compared with high-resolution measurements.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 275; 901-915
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    Effects of core perturbations on the structure of the sun (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effects of perturbing the inner part of the solar core where the hydrogen abundance has been partially depleted by nuclear burning are investigated. Small regions are mixed within the core and the evolution of the resulting luminosity and radius perturbations is followed. The sensitivity of the solar luminosity and radius to mixing events of different sizes and at different locations in the core is determined and several relationships between the luminosity and radius perturbations are examined to see if the value of one of these perturbations can be inferred from a measurement of the other. It is found that any core perturbation which alters the hydrostatic structures will immediately affect the solar luminosity and radius. The behavior of these perturbations depends on the location of the mixing event within the core. Mixing events cannot produce the decrease in the solar radius without leading to a homogeneous evolution of the solar core and/or to a prohibitively large change in the solar luminosity.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 273; 795-804
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  • 34
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    Si III line ratios in the sun (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New atomic data for Si III have been used to predict level populations and emission-line intensity ratios for electron densities and temperatures appropriate to the solar transition region. The electron impact collision rates used here are substantially larger than those previously published owing to delineation of the complex resonance structures in the low-energy collision strengths. This together with small changes in the spontaneous radiative rates produces significant changes in the calculated intensity ratios. Generally good agreement is found with observations obtained using the Naval Research Laboratory slit spectrograph aboard Skylab, electron densities from three Si III ratios and from other methods normally agreeing to 0.2 dex or better for a wide variety of solar features. For a fourth ratio, incorporating lines with a wide wavelength separation, the agreement is less satisfactory, possibly owing to uncertainties in the observational data.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 274; 420-428
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  • 35
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    Lines of Fe XII sensitive to coronal electron density (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Lines of Fe XII sensitive to coronal electron density are discussed. The lines appear in solar spectra obtained by the Naval Research Laboratory (NRL) slit spectograph flown on Skylab. These lines are due to transitions between levels of the 3s 2 3p 3 configuration and fall at the wavelengths 1242.03 A, 1349.38 A, 2169.03 A, 2405.71 A, and 2565.99 A. It is shown that the line at 2169.03 A is severely blended by a line of Ni II at heights less than 12 arcsec outside the solar limb. Above 12 arcsec the lines at 2169.03 and 2405.71 A are apparently unblended and can be used to derive electron densities. An average coronal electron pressure of 6 x 10 to the 14th/cu cm K is obtained. However, the emitting path lengths of the Fe XII lines, deduced using the electron densities and absolute intensities, are unrealistically large. The reason for this difficulty is unclear.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 273; 822-828
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  • 36
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    Determination of solar wind elemental abundances from M/Q observations during three periods in 1980 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Mass spectra in the M/Q range from 2 to 3, provided by a high-resolution mode of the ISEE-3 Plasma Composition Experiment, were evaluated for three selected periods during early 1980. The observed Ne/O ratios are compatible with estimated solar abundance ratios. In two of the three periods, the He/Ne-ratios agree with the Apollo foil results. Freezing-in temperatures for oxygen are similar to those obtained by other groups. Possible reasons for an unexpectedly high flux at M/Q = 2.4 are discussed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 88; 359-376
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  • 37
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    Solar flare X-ray spectra from the P78-1 spacecraft (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results from the high resolution solar X-ray spectrometer experiments on the P78-1 spacecraft are discussed. These results concern physical quantities such as electron temperature and density, turbulence, mass motions, and state of ionization equilibrium, characteristic of the thermal soft X-ray emitting flare plasma, and the time behavior of these quantities during flares. In addition, a brief description of the instruments is given, the plasma diagnostics used in interpreting the spectra are summarized, and the origin of the thermal soft X-ray emitting plasma is discussed in light of the P78-1 results, earlier data, and numerical simulations of magnetic flux tubes heated to solar flare temperatures.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0038-0938)
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  • 38
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    Purely coronal flare-like variations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Quasiperiodic X-ray, UV, microwave, and metric-wave variations after a solar flare on November 6, 1980 are reported and analyzed, based on observational data from SMM (HXRBS, UVSP, HXIS), GOES-2, the 100-m radiotelescope at Bonn, and the Nancay radioheliograph. The maxima of the 13 brightenings observed are listed and characterized; a comparison is made with a 'normal' flare at 17:26 UT on the same day. The HXIS and UVSP data are discussed in terms of the physical properties, X-ray flux, O V flux, and H-alpha flux. The variations are found to be mainly thermal and purely coronal, with no chromospheric (H-alpha) participation (in contrast to the 17:26 flare). Since strong X-ray emissions were observed which should have involved the chromosphere through magnetic-field-line heat conduction, it is proposed that the variations wre produced ina coronal plasmoid magnetically separate from the chromosphere. A mechanism for the evolution of such a plasmoid from the upper loops of a giant X-ray arch is discussed. An iterative HXIS-image-deconvolution process is presented in an appendix.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 85; June 198
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  • 39
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    Expected intensities of solar forbidden lines emitted from 2p(k) (k = 2, 3, 4) configurations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Predicted intensities of all significant transitions within the ground configurations of six-, seven-, and eight-electron ions are tabulated for solar conditions, on a common scale. Some applications of the table entries to line identification and emission measure analysis are presented, including proposed Mg VI classifications for the coronal lines 3488.5 A and 3502.5 A.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 85; May 1983
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  • 40
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    Heliospheric magnetic fields and plasmas (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A survey of the existing literature on heliospheric physics, covering the period 1972-1982, is presented. Attention is given to observations and theories germane to the examination of the heliosphere as a large-scale astrophysical system that is part of the earth's environment. The literature includes data and models for magnetic sectors and the large-scale magnetic field, the large-scale plasma structure, and models and observed variations in the solar wind. Consideration is also devoted to the transient and corotating streams and shocks, the composition of the solar wind, and to MHD turbulence, waves, and discontinuities. More intensive investigations of the region near 1 AU are recommended, particularly to characterize the coronal source of the solar wind. The solar polar mission will be the first to provide radial measurements for comparisons with previous exclusively ecliptic measurements of solar activities.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0034-6853)
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  • 41
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    Evidence for inhomogeneous thermal sources of two similar solar spike events of 1978 May 5 and December 4 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two short duration single spike solar events of 1978 May 5 and December 4 exhibit similar time profiles in the microwave and hard X-ray ranges, indicating emission from compact sources. Microwave spectral observations exhibit inhomogeneities present in the source parameters. The existence of fine time structures in the microwave time profiles at 10.4 GHz from Berne are interpreted as a signature of the dynamics of a disturbance traveling through the source at the ion-sound speed. Stereoscopic observations with the hard X-ray detector on the solar orbiter, Helios-2, and the Berne microwave antenna do not indicate any time lag or differences in the time profiles during the impulsive phase. This is taken as evidence for the absence of directionality of emission making beam models unlikely for short duration single spike events. Previously announced in STAR as N83-13047
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 270; July 1
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  • 42
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    Fluid motions in the solar chromosphere-corona transition region. III - Active region flows from wide slit Dopplergrams (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Large-scale velocity patterns observed in C IV in active regions show close correspondence with photospheric magnetic field patterns. In a large majority of cases, magnetic neutral lines show blueshift on their sun center side and redshift on their limbward side. The large-scale flow is consistent with widespread loop structure having downflow in both legs of the loops. Studies of individual bright loops, confirm that the flow is downward in most cases. However, an important subset of loops show flow from one end of the loop to the other.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 269; June 15
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  • 43
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    Atomic calculations for the Fe XX X-ray lines (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The atomic data presented here and in Bhatia and Mason (1980) allow the calculation of theoretical intensity ratios for all the EUV, UV, and X-ray lines from Fe XX. Tabulations are presently given for the transitions between levels in the 2s2 2p3, 2s2 2p2 3s, and 2s2 2p2 3d configurations of Fe(19+), and electron collision strengths are calculated by means of the 'distorted wave' approximation. In addition to the theoretical X-ray line intensity ratios, new spectral line identifications from a solar flare are presented.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics Supplement Series (ISSN 0365-0138); 52; April 19
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  • 44
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    Atomic calculations for Ca XVII - UV and X-ray lines (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Doschek et al. (1977) have pointed out the importance of the Ca XVII UV lines as an electron density diagnostic. Energy levels, transition probabilities, and collision strengths, are presently obtained for the 2s2, 2s 2p, 2p2, 2s 3s, 2s 3p, and 2s 3d configurations of Ca XVII, and the theoretical intensity ratios for the UV and X-ray lines are compared with observed intensities in solar flare spectra. Inconsistencies are indicated in the analysis of UV data, and discrepancies between observed and theoretical intensity ratios indicate that further studies are required. New identifications are suggested in the X-ray wavelength region.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics Supplement Series (ISSN 0365-0138); 52; April 19
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  • 45
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    Conductive flux in flaring solar chromospheres deduced from the linear polarization observations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 119; 2, Ma; Mar. 198
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  • 46
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    Models of the formation of the solar nebula (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Protostellar cloud collapse and solar nebula formation models indicate that the size of the nebula produced will be larger in terms of both gas centrifugal balance R(CF) and collapse time diffusion length R(V). From this, it can be deduced that low mass nebulas are produced if (R(V)/R(CF))-squared is much greater than unity, while nebulas result for values lower than approximately unity. The total angular momentum value distinguishes most current models of the solar nebula. Analytic expressions for the surface density, nebular mass flux and photospheric temperature distributions during the formation stage are presented for simple modes illustrating and general properties of growing protostellar disks.
    Keywords: SOLAR PHYSICS
    Type: Icarus; 53; Jan. 198
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  • 47
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    Multiple transonic solutions with a new class of shock transitions in steady isothermal solar and stellar winds (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that a new class of shock transitions arises in the transonic solutions of the steady isothermal solar wind equations when momentum deposition and/or nonradial flow tube divergence give rise to multiple critical points in the flow. These shock transitions between critical solutions occur for a certain range of the parameters which characterize the momentum deposition function. The isothermal wind equations allow multiple transonic solutions in the presence of such shock transitions, yielding a continuous solution passing through an inner critical point and solutions involving a shock transition between critical solutions. It is determined that these multiple transonic solutions have the same flow speed at the base but different supersonic flow speeds at infinity. It is found that the nonradial flow tube divergence and momentum addition are equivalent, which gives rise to multiple critical points and hence to multiple transonic solutions with shock transitions. In addition, the physical relevance of these properties are examined for astrophysical systems such as the inner solar wind, flows in extragalactic jets, and accretion discs.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 88; Mar. 1
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    Facular influences on the apparent solar shape (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The problem of the influence of faculae on apparent solar shape is examined in light of general facular contrast models. The diagonal components of the oblateness signal from the faculae observed are calculated, and it is found that the faculae can contribute a signal whose time dependence is similar to that of the Dicke and Goldenberg (1967) oblateness signal, allowing an acceptable fit to the oblateness measurements for a facular contrast within the range of acceptable values.
    Keywords: SOLAR PHYSICS
    Type: Nature; 301; Jan. 13
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  • 49
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    Numerical simulations of loops heated to solar flare temperatures. I - Gasdynamics. II - X-ray and UV spectroscopy (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NRL's Dynamic Flux Tube Model is used to numerically simulate the dynamic response of a coronal magnetic loop to an energy input of the order encountered in solar flares. The coronal plasma is heated by the deposition of flare energy at the top of the loop to more than 10 million K, yielding a conduction front that moves toward the chromosphere, where the plasma is heated by the large downward conductive flux and ablates upward to the coronal part of the loop at velocities of a few hundred km/sec. The conduction front simultaneously produces chromospheric ablation and compresses the material ahead of it. With the aid of compressional instabilities, the compressed plasma grows throughout the flare heating phase, presenting a possible source of the flare optical continuum emission which is correlated with soft X-ray radiation. The observational consequences of rapidly heated loop gas dynamic processes are discussed. In the second part of this presentation, the dynamical calculation results previously obtained are used to predict the spectral line intensities, profiles and wavelengths of several X-ray lines and the UV line of Fe XXI at 1354.1 A. Three different viewing orientations of the loop are considered.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 265
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    Impact linear polarization observed in a UV chromospheric line during a solar flare (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 265
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  • 51
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    Simultaneous ultraviolet line and hard X-ray bursts in the impulsive phase of solar flares (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 265
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  • 52
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    Fluid motions in the solar chromosphere-corona transition region. I - Line widths and Doppler shifts for C IV (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
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  • 53
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    Progress and problems in the theory of type III solar radio emission (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The experimental and theoretical status of type III solar radio emission is considered in detail. Very recent developments which are relevant to the underlying plasma physics are emphasized. In particular, the identity of the submegahertz emissions as fundamental, or second harmonic, the degree of correlation between emissivities, electron streams, and plasma (Langmuir) waves, paradoxes concerned with the time-ordering of these phenomena, and the role of background density irregularities and ion-acoustic turbulence in the solar wind, are discussed. From the theoretical point of view, the current picture of the underlying Langmuir turbulence, including such effects as the interaction between Langmuir waves and stream electrons, induced scatter off ions, and strong turbulence effects such as modulational instability and soliton collapse, is discussed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 89; 403-442
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  • 54
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    Neutrons and Gamma Rays from Solar Flares (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: The theory of neutron and gamma-ray production in flares is reviewed and comparisons of the calculations with data are made. The principal conclusions pertain to the accelerated proton and electron numbers and spectra in flares and to the interaction site of these particles in the solar atmosphere. For the June 21, 1980 flare, from which high-energy neutrons and high-energy ( MeV) photons were seen, the electron-to-proton ratio is energy dependent and much smaller than unity at energies greater than 1 MeV. The interaction site of these particles appears to be the solar chromosphere.
    Keywords: SOLAR PHYSICS
    Type: Goddard Space Flight Center Contrib. to the Univ. of Calif., Santa Cruz Summer Workshop on High Energy Transients; 13 p
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  • 55
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    On the field configuration in magnetic clouds (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Interplanetary magnetic clouds are represented by cylindrically symmetric equilibrium solutions of the MHD equations. The radial magnetic pressure gradient of the force free field is balanced by the curvature stress. The field inside is essentially parallel to the cylinder axis, far outside it is oriented in azimuthal direction. These configurations therefore differ from the nonselfconsistent model where the field lines are tightly wound even near the axis.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 731-733
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  • 56
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    Interaction of the plasma tail of comet Bradfield 1979L on 1980 February 6 with a possibly flare-generated solar-wind disturbance (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Solar wind plasma data from the ISEE-3 and Helios 2 spacecraft were examined to explain a uniquely rapid 10 deg turning of the plasma tail of comet Bradfield 1979L on 1980 February 6. It was suggested that the tail position angle change occurred in response to a solar wind velocity shear across which the polar component changed by approx. 50 km s-1. The present activity was caused by noncorotating, disturbed plasma flows probably associated with an Importance 1B solar flare.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 737-742
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    Velocity profiles of interplanetary shocks (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The type 2 radio burst was identified as a shock propagating through solar corona. Radio emission from shocks travelling through the interplanetary (IP) medium was observed. Using the drift rates of IP type II bursts the velocity characteristics of eleven shocks were investigated. It is indicated that shocks in the IP medium undergo acceleration before decelerating and that the slower shocks take longer to attain their maximum velocity.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 703-709
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    Associations between coronal mass ejections and interplanetary shocks (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Nearly continuous complementary coronal observations and interplanetary plasma measurements for the years 1979-1982 are compared. It is shown that almost all low latitude high speed coronal mass ejections (CME's) were associated with shocks at HELIOS 1. Some suitably directed low speed CME's were clearly associated with shocks while others may have been associated with disturbed plasma (such as NCDE's) without shocks. A few opposite hemisphere CME's associated with great flares seem to be associated with shocks at HELIOS.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 693-702
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  • 59
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    Quasi-steady solar wind dynamics (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Progress in understanding the large scale dynamics of quasisteady, corotating solar wind structure was reviewed. The nature of the solar wind at large heliocentric distances preliminary calculations from a 2-D MHD model are used to demonstrate theoretical expectations of corotating structure out to 30 AU. It is found that the forward and reverse shocks from adjacent CIR's begin to interact at about 10 AU, producing new shock pairs flanking secondary CIR's. These sawtooth secondary CIR's interact again at about 20 AU and survive as visible entities to 30 AU. The model predicts the velocity jumps at the leading edge of the secondary CIR's at 30 AU should be very small but there should still be sizable variations in the thermodynamic and magnetic parameters. The driving dynamic mechanism in the distant solar wind is the relaxation of pressure gradients. The second topic is the influence of weak, nonimpulsive time dependence in quasisteady dynamics. It is suggested that modest large scale variations in the coronal flow speed on periods of several hours to a day may be responsible for many of the remaining discrepancies between theory and observation. Effects offer a ready explanation for the apparent rounding of stream fronts between 0.3 and 1.0 AU discovered by Helios.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 675-691
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    Modeling of transient disturbances in coronal-streamer configurations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Numerical simulations of the formation and propagation of mass ejection, loop transients in coronal streamers are discussed. The simulations are accomplished with numerical solutions of the single fluid, ideal MHD equations of motion in the meridional plane. The streamer is produced by simulating the relaxation of an initially radial hydrodynamic flow coupled with a dipole magnetic field. The simulated transient then results from an energy release at the base of the streamer. The legs of the loop transient produced remain essentially stationary while the loop expands mainly in the radial direction with velocities of 400 to 750 km s-1. Once the leading edge of the transient has passed out of the lower corona, the initial streamer configuration is restored after 15 to 24 hours. A second energy release 2 hours later than, and with an energy release identical to, the first does not produce a significant coronal disturbance.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 667-673
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    Minor constituents in the solar wind originating from plasma-dust interactions (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Atoms, molecules, and atomic and molecular ions generated by solar wind interactions with dust grains of the zodiacal cloud are discussed. The main processes leading to the generation of these particles are described and relevant methods of observation are examined.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 643-645
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    Mixed solar wind originating from coronal regions of different temperatures (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Ionization states of elements in the solar wind are often used to determine thermal gradients in the lower corona. This method is based on the assumption, that in the beginning, solar wind material has a homogeneous temperature determining the original charge state of elements. Features in M/Q-spectra which might appear if the above assumption is violated are investigated and compared with observational evidence.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 613-622
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    Solar wind minor ions: Recent observations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Systematic studies show that the minor ions generally travel with a common bulk speed and have temperatures roughly proportional to their masses. It was determined that (3)He(++) content varies greatly; (3)He(++)/(4)He(++) ranges from as high as 10(-12) values to below 2 x 10(-4). In some solar wind flows which can be related to energetic coronal events, the minor ions are found in unusual ionization states containing Fe(16+) as a prominent ion, showing that the states were formed at unusually high temperatures. Unexpectedly, in a few flows substantial quantities of (4)He(+) were detected, sometimes with ions identifiable as O(2+) and O(3+). Surprisingly, in some of these examples the ionization state is mixed showing that part of the plasma escaped the corona without attaining the usual million-degree temperatures while other parts were heated more nearly in the normal manner. Additionally, detailed studies of the minor ions increased our understanding of the coronal expansion. For example, such studies contributed to identifying near equatorial coronal streamers as the source of solar wind flows between high speed streams.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 573-589
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    The interplanetary hydrogen and helium glow and the inferred interstellar gas properties (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Observations of the interplanetary hydrogen and helium glow have been obtained by a number of spacecraft and rocket experiments during the past fifteen years. Important results have been established on the temperature, density, velocity, spatial dependence, and hydrogen to helium ratio. However, only four spacecraft launched to date are investigating the outer solar system and of these four the Pioneer 10 spacecraft is the farthest out at 28 A.U. Observations from this spacecraft at great distances have permitted an improved analysis of the effects which are only evident at large distances from the Sun. Perhaps the most significant result in this regard is the clear evidence of the importance of multiple scattering of solar Ly-alpha; an effect which has not been observed in earlier work. Ignoring this effect can lead to a gross overestimate of the local galactic glow. Current best estimates of the galactic glow and the local interstellar wind parameters obtained by the Pioneer 10 photometer at great distances are presented, in addition to complementary experimental observations of particular interest.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 557-563
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    Theory of interstellar medium diagnostics (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The theoretical interpretation of observed interplanetary resonance luminescence patterns is used as one of the must promising methods to determine the state of the local interstellar medium (LISM). However, these methods lead to discrepant results that would be hard to understand in the framework of any physical LISM scenario. Assuming that the observational data are reliable, two possibilities which could help to resolve these discrepancies are discussed: (1) the current modeling of resonance luminescence patterns is unsatisfactory and has to be improved, and (2) the extrapolated interstellar parameters are not indicative of the unperturbed LISM state, but rather designate an intermediate state attained in the outer regions of the solar system. It is shown that a quantitative treatment of the neutral gas-plasma interaction effects in the interface between the heliospheric and the interstellar plasmas is of major importance for the correct understanding of the whole complex.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 541-551
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    The radial evolution of the solar wind, 1-10 AU (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The interplanetary plasma and magnetic field observations from 1 to 10 AU are reviewed. Over this distance no clear reduction in average speed is seen. The range of wind speeds becomes smaller though high speed streams are still observed. The density, temperature and magnetic field profiles become dominated by the large values seen in the co-rotating interaction regions. The temperature falls more slowly than would be expected from a simple, adiabatic model. Co-rotating shocks appear beyond approximately 3 AU in Voyager data as opposed to beyond approximately 1.5 AU in the Pioneer data. Reverse shocks appear later than forward shocks; reverse shocks do not begin to appear until approximately 4 AU; reverse shocks appear to decay more rapidly than forward shocks. No clear effect due to interaction with the interstellar medium was seen in this radial range.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 509-519
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    The average solar wind in the inner heliosphere: Structures and slow variations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Measurements from the HELIOS solar probes indicated that apart from solar activity related disturbances there exist two states of the solar wind which might result from basic differences in the acceleration process: the fast solar wind (v 600 kms(-)1) emanating from magnetically open regions in the solar corona and the "slow" solar wind (v 400 kms(-)1) correlated with the more active regions and its mainly closed magnetic structures. In a comprehensive study using all HELIOS data taken between 1974 and 1982 the average behavior of the basic plasma parameters were analyzed as functions of the solar wind speed. The long term variations of the solar wind parameters along the solar cycle were also determined and numerical estimates given. These modulations appear to be distinct though only minor. In agreement with earlier studies it was concluded that the major modulations are in the number and size of high speed streams and in the number of interplanetary shock waves caused by coronal transients. The latter ones usually cause huge deviations from the averages of all parameters.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 489-507
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    Radio evidence for interplanetary streamers in the range 10-170 solar radii (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Type III radio storms are observed by the radio experiment on board the International Sun Earth Explorer 3 out to 0.5-0.8 AU from the Sun, at a rate of 2 to 3 storms per solar rotation near solar maximum. They correlate with the type I and type III radio storms observed at higher frequencies, originating closer to the Sun. They are associated with an almost continuous injection of suprathermal electrons into the interplanetary medium. Some of the properties of the regions where the particles propagate are discussed, using the radio emission as a tracer.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 469-474
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    Interplanetary scintillation observations of the solar wind close to the Sun and out of the ecliptic (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A brief review is given of recent developments in the observation of the solar wind by the method of interplanetary scintillation. The emphasis is on observations of the velocity structure, the electron density and the effect of propagating disturbances in the interplanetary medium as detected principally by intensity and phase scintillation and by spectral broadening.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 453-468
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    Electron heating at interplanetary shocks (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Data for 41 forward interplanetary shocks show that the ratio of downstream to upstream electron temperatures. T sub e (d/u) is variable in the range between 1.0 (isothermal) and 3.0. On average, (T sub e (d/u) = 1.5 with a standard deviation, sigma e = 0.5. This ratio is less than the average ratio of proton temperatures across the same shocks, (T sub p (d/u)) = 3.3 with sigma p = 2.5 as well as the average ratio of electron temperatures across the Earth's bow shock. Individual samples of T sub e (d/u) and T sub p (d/u) appear to be weakly correlated with the number density ratio. However the amounts of electron and proton heating are well correlated with each other as well as with the bulk velocity difference across each shock. The stronger shocks appear to heat the protons more efficiently than they heat the electrons.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 403-411
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    Electrostatic waves and anomalous transport in the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: In situ measurements of fluctuation spectra and particle distribution functions have now been carried out throughout interplanetary space. The link between these observations is established by theories of wave particle interaction. Linear instability analysis for the actual nonMaxwellian particle distribution functions and an examination of the velocity dependence of microscopic diffusion coefficients form the basis of such an investigation. It is described in more detail for the short wavelength, ion acoustic like turbulence which is found by linear instability analysis to correspond to the observed electrostatic fluctuations. Of the transport processes associated with these fluctuations, electron heat conduction and electron ion energy transfer are of particular importance for macroscopic solar wind expansion. These effects are studied with the aid of an anomalous transport theory. This theory (Dum, 1978 a,b) is based on the dominance of elastic scattering of electrons by fluctuations, similar to (enhanced) electron ion collisions. It has a much wider range of applicability than classical transport theory, which assumes dominance of Coulomb collisions for elastic and inelastic scattering.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 369-376
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    Measurement of macroscopic plasma parameters with a radio experiment: Interpretation of the quasi-thermal noise spectrum observed in the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The ISEE-3 SBH radio receiver has provided the first systematic observations of the quasi-thermal (plasma waves) noise in the solar wind plasma. The theoretical interpretation of that noise involves the particle distribution function so that electric noise measurements with long antennas provide a fast and independent method of measuring plasma parameters: densities and temperatures of a two component (core and halo) electron distribution function have been obtained in that way. The polarization of that noise is frequency dependent and sensitive to the drift velocity of the electron population. Below the plasma frequency, there is evidence of a weak noise spectrum with spectral index -1 which is not yet accounted for by the theory. The theoretical treatment of the noise associated with the low energy (thermal) proton population shows that the moving electrical antenna radiates in the surrounding plasma by Carenkov emission which becomes predominant at the low frequencies, below about 0.1 F sub P.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 377-383
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    Radial evolution of ion distribution functions (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A survey of solar wind ion velocity distributions and derived parameters (temperature, ion differential speed, heat flux, adiabatic invariants) is presented with emphasis on the heliocentric distance range between 0.3 and 1 AU traversed by the Helios solar probe. The radial evolution of nonthermal features are discussed which are observed to be most pronounced at perihelion. Within the framework of quasilinear plasma theory, wave particle interactions that may shape the ion distributions are considered. Some results of a self consistent model calculation are presented accounting for ion acceleration and heating by resonant momentum and energy exchange with ion cyclotron and magnetosonic waves propagating away from the Sun along the interplanetary magnetic field. Another tentative explanation for the occurrence of large perpendicular proton temperatures is offered in terms of heating by Landau damping of lower hybrid waves.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 355-367
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    Solar cycle variations in the interplanetary magnetic field (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: ISEE 3 interplanetary magnetic field measurements have been used to extend the NSSDC hourly averaged IMF composite data set through mid-1982. Most of sunspot cycle 20 (start:1964) and the first half of cycle 21 (start:1976) are now covered. The average magnitude of the field was relatively constant over cycle 20 with approx. 5-10% decreases in 1969 and 1971, when the Sun's polar regions changed polarity, and a 20% decrease in 1975-6 around solar minimum. Since the start of the new cycle, the total field strength has risen with the mean for the first third of 1982 being about 40% greater than the cycle 20 average. As during the previous cycle, an approx. 10% drop in IMF magnitude accompanied the 1980 reversal of the solar magnetic field. While the interplanetary magnetic field is clearly stronger during the present solar cycle, another 5-7 years of observations will be needed to determine if cycle 21 exhibits the same modest variations as the last cycle. Accordingly, it appears at this time that intercycle changes in IMF magnitude may be much larger than the intracycle variations.
    Keywords: SOLAR PHYSICS
    Type: Solar Wind Five; p 323-331
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    The winds and coronae of early-type stars (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The properties of the winds of hot stars as derived from radio, ultraviolet and X-ray observations is presented. Special focus is given to observations that test line driven wind theory. In this theory the wind properties are determined by the stellar effective temperature and surface gravity, but not parameters that specify the mechanical or wave fluxes from the star. Alternate explanations of the X-ray emission from the early-type stars are discussed. Evidence is given for the presence of coronal zones at the base of the stellar winds.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 263-278
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    Theory of winds in late-type evolved and pre-main-sequence stars (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Recent observational results confirm that many of the physical processes which are known to occur in the Sun also occur among late-type stars in general. One such process is the continuous loss of mass from a star in the form of a wind. There now exists an abundance of either direct or circumstantial evidence which suggests that most (if not all) stars in the cool portion of the HR diagram possess winds. An attempt is made to assess the current state of theoretical understanding of mass loss from two distinctly different classes of late-type stars: the post-main-sequence giant/supergiant stars and the pre-main-sequence T Tauri stars. Toward this end, the observationally inferred properties of the wind associated with each of the two stellar classes under consideration are summarized and compared against the predictions of existing theoretical models. Although considerable progress has been made in attempting to identify the mechanisms responsible for mass loss from cool stars, many fundamental problems remain to be solved.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 241-262
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    Magnetohydrodynamic modeling of coronal structure and expansion (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The presence of a magnetic field in the corona adds structure to the solar wind and almost certainly plays an important role in the energetics of the flow. Analytical and numerical modeling of gas-magnetic field interactions as used to compute steady, global flow are discussed. The approach used in, and results from a recent global model (Steinolfson, Suess and Wu, 1982) are discussed. Ideas on the most effective ways to improve the physical content and numerical efficiency of these models are outlined. Solutions of the MHD equations are discussed only in order to find steady-state flows, even though this often entails solving time-dependent equations.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 183-198
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    The collapse of the local, Spitzer-Haerm formulation and a global-local generalization for heat flow in an inhomogeneous, fully ionized plasma (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The breakdown of the classical (CBES) field aligned transport relations for electrons in an inhomogeneous, fully ionized plasma as a mathematical issue of radius of convergence is addressed, the finite Knudsen number conditions when CBES results are accurate is presented and a global-local (GL) way to describe the results of Coulomb physics moderated conduction that is more nearly appropriate for astrophysical plasmas are defined. This paper shows the relationship to and points of departure of the present work from the CBES approach. The CBES heat law in current use is shown to be an especially restrictive special case of the new, more general GL result. A preliminary evaluation of the dimensionless heat function, using analytic formulas, shows that the dimensionless heat function profiles versus density of the type necessary for a conduction supported high speed solar wind appear possible.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 163-182
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    Role of thermal conduction in the acceleration of the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The thermal and suprathermal processes involving solar wind electrons are discussed from a theoretical point of view. A model for the electron distribution function, f(e), based on the solutions of the Boltzmann equation in Krook's approximation is outlined: the angular and energy dependences of for various distances from the Sun between the coronal base and the Earth are presented with the express purpose of obtaining the radial profile of the heat flux generated by the suprathermals. The basic fluid-dynamical equations for the solar wind plasma as a whole along any given magnetic field line are solved. Results are in good agreement with observations. The predicted density and temperature profiles for positive ions exhibit the characteristics of recent measurements, both in the corona (above the coronal holes) and between 0.3 and 1 A.U. (the Helios region). It is concluded that the suprathermal electrons play an important role in the formation and the dynamics of the solar wind.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 149-162
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    Interplanetary Alfvenic fluctuations: A statistical study of the directional variations of the magnetic field (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Magnetic field data from HELIOS 1 and 2 are used to test a stochastic model for Alfvenic fluctuations recently proposed. A reasonable matching between observations and predictions is found. A rough estimate of the correlation length of the observed fluctuations is inferred.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 99-104
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    Alfven solitons in the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A nonlinear Alfven soliton solution of the MHD equations is presented. This solution represents the final state of modulationally unstable Alfven waves. A model of the expected turbulent spectrum due to a collection of such solitons is briefly described.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 93-98
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    Observations of hydromagnetic turbulence in the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: MHD turbulence is studied by analyzing magnetic field and plasma observations from Helios-1 and -2 at minimum solar activity. The steady conditions in the plasma flows and the magnetic field sector structure in 1975/1976 facilitate an investigation of the radial evolution of the turbulence from 0.29 to 1AU. In high speed streams the fluctuations in the solar wind velocity v and the magnetic field b are highly correlated (the correction coefficient almost being one), which indicates that the turbulence is mainly Alfvenic in high speed plasma. While some general fluctuation properties remain essentially unchanged from 0.29 to 1AU, power spectral analysis reveals a different frequency composition of the Alfvenic turbulence at different heliocentric distances. At 0.3AU much more 'high' frequency fluctuations contribute to the total power in the magnetic field and velocity fluctuations than at 1AU. The contributions of field magnitude fluctuations are found to be distance and frequency dependent. Magnetic field spectra with an extended frequency range up to 470Hz show certain frequency bands, where the steepness of the spectra is independent of the helicocentric distance.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 81-92
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  • 83
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    Magnetohydrodynamic turbulence in the solar wind (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Recent work in describing the solar wind as an MHD turbulent fluid has shown that the magnetic fluctuations are adequately described as time stationary and to some extent as spatially homogeneous. Spectra of the three rugged invariants of incompressible MHD are the principal quantities used to characterize the velocity and magnetic field fluctuations. Unresolved issues concerning the existence of actively developing turbulence are discussed.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 73-80
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    Coronal transients in FE XIV 5303A: First two-dimensional photoelectric ground-based observations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: An observational program was undertaken at Sacramento Peak Observatory to photoelectrically detect coronal transients. Continuous observations are made in the Fe XIV 5303A green line, utilizing the 40 cm coronagraph and the Photoelectric Coronal Photometer. Scans at three heights above the limb are combined to form a low resolution picture of the greenline corona every 20 to 30 minutes. Difference pictures, relative to an initial scan, are generated to search for sudden changes in the corona. The first few days of operation of this program have yielded three low-lying events ( 1.55 solar radii) following minor chromospheric activity (a surge and eruptive prominences), which propagated up through the corona with velocities on the order of 100 km/s.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 63-67
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    HRTS observations of the fine structure and dynamics of the solar chromosphere and transition zone (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Arc-second UV observations of the Sun by the NRL High Resolution Telescope and Spectrograph (HRTS) have led to the discovery of dynamic fine structures such as 400 km/s coronal jets and chromospheric jets (spicules) and have provided new information about the structure and dynamics of the transition zone. These observations are reviewed and their relevance to the origin of the solar wind is discussed.
    Keywords: SOLAR PHYSICS
    Type: JPL Solar Wind Five; p 33-44
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    Skylab observations of the solar C I multiplets at 1560- and 1657-A (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Skylab spectrograph profile observations of the solar C I multiplets are presented, and the profile variations from center to limb and at various heights above the quiet solar limb are noted. These lines are of interest both because they are formed in the midchromosphere, thereby providing checks and constraints on chromospheric models, and because they are sensitive to the magnitude of the nonthermal microvelocities included in theoretical calculations. The present observations are compared with the C I profiles calculated by Shine et al (1978), discussing the many inconsistencies that emerge, notably between the observed and computed 1560/1657-A ratio and in the center-to-limb and above-the-limb variations of the integrated intensity. The multiplet central cores are discussed in terms of several microturbulent velocity structures.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 275; 892-900
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    Solar wind disturbances caused by solar flares - Equatorial plane (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The propagation of solar wind disturbances caused by single, double and six successive flares in the dipolar and quadrupolar patterns of the interplanetary magnetic field (IMF) and the associated solar wind flow is studied. This study is based on a kinematic and empirical method developed by Hakamada and Akasofu (1982). Each flare is characterized by six parameters (such as the highest speed flow, its extent and duration). The successive IMF patterns in the equatorial plane of the heliosphere during a time span of 0.5-60 days after flares are presented for a variety of flares. The solar wind speed and IMF magnitude are given as a function of distance along a radial line fixed in space and also as a function of time at several points fixed in space (simulating approximately space probe observations). Some of the results are qualitatively compared with recent space probe observations, demonstrating fair similarity with the observed time profiles of solar wind speed variations over a wide range of both distances (0-10 AU) and time spans (60 days). The method provides a first-order construction, temporal and spatial, of flare-induced shocks and their multiple interactions with each other, as well as with the corotating interaction regions.
    Keywords: SOLAR PHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; 1435-145
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  • 88
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    Stochastic three-wave interaction in flaring solar loops (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A model is proposed for the dynamic structure of high-frequency microwave bursts. The dynamic component is attributed to beams of precipitating electrons which generate electrostatic waves in the upper hybrid branch. Coherent upconversion of the electrostatic waves to electromagnetic waves produces an intrinsically stochastic emission component which is superposed on the gyrosynchrotron continuum generated by stably trapped electron fluxes. The role of the density and temperature of the ambient plasma in the wave growth and the transition of the three wave upconversion to stochastic, despite the stationarity of the energy source, are discussed in detail. The model appears to reproduce the observational features for reasonable parameters of the solar flare plasma.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 275; 374-390
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  • 89
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    The solar wind ionization state as a coronal temperature diagnostic (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The 'frozen' solar wind ionization state within a few solar radii of the photosphere suggests that ion measurements at 1 AU may yield information on the electron temperature conditions at the base of the coronal expansion. The freezing-in process is examined in light of traditional assumptions as to coronal expansion, where electron temperature decreases monotonically with height, the bulk flow of all charge states of a given ion species are equal to the proton speed, and the ion outflow is spherically symmetric. The consequences of the relaxation of these assumptions include the underestimation of the magnitude of a temperature maximum occurring near the freezing-in radius. Because it is associated with high speed, low density flow, an areal divergence that is faster than that in a spherical outflow lowers the ionization state freezing-in level relative to that which is typical in spherically symmetric expansion.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 275; 354-366
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  • 90
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    Possible observation of a disconnected magnetic structure in a coronal transient (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Solar Maximum Mission coronagraph/polarimeter observations of the coronal transient of March 15-16, 1980, which show a bright front convex toward the sun propagating out through the corona at 175 km/sec, are reported. A fan-shaped bright region connecting this front to the inner corona collapses into a narrow, bright ray over the next few hours. These observations are interpreted as resulting from the disconnection of magnetic loops from the underlying prominencelike loop structures seen rising earlier in the event. Other similar inverted arches exist in the C/P data, but are usually seen with poorer temporal resolution.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10210-10
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  • 91
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    Turbulent heating in solar cosmic ray theory (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The heating of minor ions in solar flares by wave-wave-particle interaction with Langmuir waves, or ion acoustic waves, can be described by a diffusion equation in velocity-space for the particle distribution function. The dependence of the heating on the ion charge and mass, and on the composition of the plasma, is examined in detail. It is found that the heating mechanisms proposed by Ibragimov and Kocharov cannot account for the enhanced abundances of heavy elements in the solar cosmic rays.
    Keywords: SOLAR PHYSICS
    Type: NASA-TM-85074 , NAS 1.15:85074
    Format: application/pdf
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  • 92
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    Acceleration and confinement of energetic particles in the 1980 June 7 solar flare (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Pulsations with large amplitude and duration have been observed during the hard X-ray and microwave radio bursts associated with the 1980 June 7 solar flare. The high time resolution measurements of 20-800 keV X-rays were made with the X-ray spectrometers aboard the ISEE 3 and P78-1 spacecraft. The radio measurements, covering metric to microwave wavelengths, were made at the Nobeyama and Toyokawa observatories in Japan. The temporal evolution of the X-ray and radio spectra and the polarization and spatial structure of the microwave source have been examined. The following interpretation is found to be consistent with the observations: (1) the variations in the electron acceleration/injection spectrum are responsible for the observed variations in the hard X-ray and microwave emissions; (2) the locations of the hard X-ray and microwave sources are probably different, the X-ray source being located at a lower altitude.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 271; Aug. 1
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  • 93
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    Thick-target bremsstrahlung interpretation of short time-scale solar hard X-ray features (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Steady-state analyses of bremsstrahlung hard X-ray production in solar flares are appropriate only if the lifetime of the high energy electrons in the X-ray source is much shorter than the duration of the observed X-ray burst. For a thick-target nonthermal model, this implies that a full time-dependent analysis is required when the duration of the burst is comparable to the collisional lifetime of the injected electrons, in turn set by the lengths and densities of the flaring region. In this paper we present the results of such a time-dependent analysis, and we point out that the intrinsic temporal signature of the thick-target production mechanism, caused by the finite travel time of the electrons through the target, may indeed rule out such a mechanism for extremely short duration hard X-ray events.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 271; Aug. 1
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  • 94
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    High resolution telescope and spectrograph observations of solar fine structure in the 1600 A region (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: High spatial resolution spectroheliograms of the 1600 A region obtained during the HRTS rocket flight of 1978 February 13 are presented. The morphology, fine structure, and temporal behavior of emission bright points (BPs) in active and quiet regions are illustrated. In quiet regions, network elements persist as morphological units, although individual BPs may vary in intensity while usually lasting the flight duration. In cell centers, the BPs are highly variable on a 1 minute time scale. BPs in plages remain more constant in brightness over the observing sequence. BPs cover less than 4 percent of the quiet surface. The lifetime and degree of packing of BPs vary with the local strength of the magnetic field.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 270; July 15
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  • 95
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    Magnetic rotation of the solar photosphere (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Magnetograms made at Mt. Wilson Observatory from January 1967 to May 1982 are crosscorrelated in 34 latitude strips at 1-4-day increments to determine the rotation of magnetic features in the solar photosphere. The data are smoothed by averaging corresponding correlations and calculating rotation from the displacement of the averaged-correlation maximum; the usefulness and validity of this procedure are discussed. No significant time variation or field dependence is found for the period of the observations, at least to the accuracy of the calculated means (variance of from about 2 m/sec at low latitudes to about 10 m/sec near the poles). The rotation function omega at solar latitude phi is shown to be 2.902 0.464 sin sq phi - 0.328 sin to the 4th phi microrad/sec, in agreement with the Mt. Wilson Doppler profile near the poles and with the sunspot determination of Newton and Nunn (1951) at sunspot latitudes, where the Doppler estimate is about 30 m/sec slower.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 270; July 1
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  • 96
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    Some spectral plasma diagnostics for prominences and structures in the middle chromosphere (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The present investigation is concerned with the statistical equilibrium of the low-lying levels of Na, Sr(+), and Ba(+) under conditions appropriate to structures just above the solar surface. The solar and atomic data required for this objective are largely available with an adequate precision. However, the metastable (2)D term photoionization cross sections had to be calculated. In the calculations a variant of the scaled Thomas-Fermy method suggested by Kahler (1971) was used. The Na and Sr(+) resonance lines are readily measurable in ordinary prominences. The Ba(+) are weak. It is shown that the ratio of Na to Sr(+) resonance-line integrated intensities provides a useful and sensitive electron-density diagnostic for prominences, yielding values in the neighborhood of 10 to the 11th per cu cm. The statistical equilibrium solutions are applied to an analysis of data from the flash spectrum at eclipse.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 269; June 15
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  • 97
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    The impulsive phase of solar flares. II - Characteristics of the hard X-rays (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The results of an investigation into the electron distribution in the general non-thermal models of solar flares were used to calculate the characteristics of the impulsive hard X-rays. The height distribution, the spectrum, the polarization, and directivity of the X-rays were observed and how these X-ray characteristics are affected by the parameters defining the model was investigated. An expression is obtained for the X-ray intensity as a function of source height which is an excellent fit under certain constraints. Some available data with spatial resolution are examined and it is shown that it is possible to reproduce these data adequately with the non-thermal model and to determine the values of the parameters describing the flares. Previously announced in STAR as N82-34328
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 269; June 15
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  • 98
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    VLA observations of a solar active region and coronal loops (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: In May 1981, observations of a solar active region at 6 cm and 20 cm were conducted with the aid of a Very Large Array (VLA). It was found that the 6 cm emission was associated with sunspots and transverse magnetic fields between spots. The 20 cm emission came from elongated sources connecting regions of opposite magnetic polarity. The sources of the emission at 20 cm could be identified as coronal loops. A model for hydrostatic loops proposed by Rosner et al. (1978) was employed to determine a likely mechanism for the emission at 20 cm. It was found that a two-component model of bremsstrahlung emission from the feet and gyroresonance emission from the top of the loops can satisfactorily explain the observations.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 269; June 15
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  • 99
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    Turbulent resistive heating of solar coronal arches (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The possibility that coronal heating occurs by means of anomalous Joule heating by electrostatic ion cyclotron waves is examined, with consideration given to currents running from foot of a loop to the other. It is assumed that self-fields generated by the currents are absent and currents follow the direction of the magnetic field, allowing the plasma cylinder to expand radially. Ion and electron heating rates are defined within the cylinder, together with longitudinal conduction and convection, radiation and cross-field transport, all in terms of Coulomb and turbulent effects. The dominant force is identified as electrostatic ion cyclotron instability, while ion acoustic modes remain stable. Rapid heating from an initial temperature of 10 eV to 100-1000 eV levels is calculated, with plasma reaching and maintaining a temperature in the 100 eV range. Strong heating is also possible according to the turbulent Ohm's law and by resistive heating.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 269; June 15
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  • 100
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    The solar absolute spectral irradiance 1150-3173 A - May 17, 1982 (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The full-disk solar spectral irradiance in the spectral range 1150-3173 A was obtained from a rocket observation above White Sands Missile Range, NM, on May 17, 1982, half way in time between solar maximum and solar minimum. Comparison with measurements made during solar maximum in 1980 indicate a large decrease in the absolute solar irradiance at wavelengths below 1900 A to approximately solar minimum values. No change above 1900 A from solar maximum to this flight was observed to within the errors of the measurements. Irradiance values lower than the Broadfoot results in the 2100-2500 A spectral range are found, but excellent agreement with Broadfoot between 2500 and 3173 A is found. The absolute calibration of the instruments for this flight was accomplished at the National Bureau of Standards Synchrotron Radiation Facility which significantly improves calibration of solar measurements made in this spectral region.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 20
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