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  • Data
  • Other Sources  (563)
  • SOLAR PHYSICS  (563)
  • 1980-1984  (563)
  • 1950-1954
  • 1983  (310)
  • 1980  (253)
  • 1952
  • 1
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    The measurement of global scale surface dynamics (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The SCADM mission implicitly contains a requirement for a fundamentally new type of satellite instrument: a very sensitive (approximately 1 m s/1) imaging velocity detector. This is needed to measure global oscillations and global circulation patterns, but the sensitivity requirement is so severe that it has not yet been met even with ground based instruments. In this presentation, the various possible sources of noise and other errors in such a device are considered, and the more detailed instrumental requirements are developed. This leads to the conceptual design of a velocitygraph that appears to achieve the necessary sensitivity and imaging capability within a resonable weight and volume.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 147-157
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  • 2
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    The opportunities offered by SCADM for the study of surface phenomena related to interior structure and dynamics (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The physical processes to be probed by experiments may be grouped as large scale flows, oscillations, and chromospheric/coronal diagnostics. While the fundamental concerns and observational equipments are similar within each class, different investigations may tell different things about the Sun. Observational requirements are listed for experiments to study (1) plasma-magnetic field interactions; (2) interior structure via oscillations; (3) chromospheric and coronal tracers; (4) rotation, meridional flows, and giant cells; (5) the depth dependence of rotation; (6) EUV luminosity; (7) intensity fluctuations and tracers; and (8) diameter oscillations, the effects of noise and timestring on experiment results are assessed.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 101-135
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  • 3
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    Observable solar features which provide clues to the state of the solar dynamo (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Space experiments are suggested to better monitor the solar dynamo and solar luminosity variations. Polar and other magnetic fields, sunspots, coronal holes, filaments and other observable solar and solar wind phenomena can provide us with important links to test and discover physical mechanisms which relate solar activity to terrestrial weather, climate, and possibly population variations.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 85-100
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  • 4
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    Overview on the study of the solar cycle from space (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Recent insights into the workings of the solar system are reviewed as factors to be considered when formulating key questions to be answered during a large scale program to study the solar cycle. The main objectives of the Solar Cycle and Dynamics Mission are to determine the causes (physical origins and mechanisms) of the solar cycle and the effects of these mechanisms on the heliosphere, the vast region that includes the corona, interplanetary medium, and the terrestrial environment. The mission should be able to obtain synoptic data on solar variability associated with the cycle, and over at least a fraction of a single 11-year cycle.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 31-42
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  • 5
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    Contributions of SCADM to solar-terrestrial physics (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The many different aspects of solar terrestrial physics are summarized. The possible influence of variations in the solar outputs on the terrestrial climate, and the role for SCADM in such studies is emphasized. The use of SCADM to provide detailed information on variations in the solar outputs over a sizeable fraction of the solar cycle, and on the physics of the convection layer of the Sun is discussed.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 277-289
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  • 6
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    X-ray bright points and the solar cycle (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The shape of the Sun's activity spectrum is such that the majority of all magnetic flux emerging at the surface comes in the form of bright points, i.e., regions living less than two days. Examination of soft X-ray data obtained from 1970 to 1978 shows that the number of bright points appears to be anticorrelated with traditional activity indices, such as sunspot number; the anticorrelation persists after corrections are made for obscuration by active regions. Comparison of X-ray data with KPNO magnetograms shows that to within a factor of two, the average total amount of magnetic flux emerging over the full Sun is constant through the entire period of observation. The Solar cycle therefore appears to be more an oscillation in the wavenumber distribution of emerging flux than of the total quantity of magnetic flux produced.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 75-83
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  • 7
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    Dynamics of the solar interior and the solar dynamo (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The solar convection zone is the origin of most of the variations in solar output observed or suspected to occur. The Sun's magnetic field is rooted there, and solar activity and the solar cycle are generated and maintained there. Changes in the magnetic fields which reach into the solar atmosphere and beyond to interplanetary space are largely determined by the dynamo action of velocity fields in the convection zone. If changes in solar luminosity occur on time scales of months to millenia, such changes probably have their origin in the changing dynamics of the convection zone, either as cause of or in response to long term changes in the level of solar activity. Fluctuations would occur in the rate at which energy is brought to the surface by convection, and the solar diameter would be slightly modified. To describe and ultimately understand the global workings of the solar dynamo requires simultaneous high quality photospheric observations of solar velocities, magnetic fields, intensity patterns, luminosity and various radiative outputs. The observations must be nearly continuous in time and of long duration-most or all of a solar cycle. Such a measurement program should be a major part of the proposed Solar Cycle and Dynamics Mission.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 3-11
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  • 8
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    A solar activity monitoring platform for SCADM (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The adaptation of proven space probe technology is proposed as a means of providing a solar activity monitoring platform which could be injected behind the Earth's orbital position to give 3 to 6 days advanced coverage of the solar phenomenon on the backside hemisphere before it rotates into view and affects terrestrial activities. The probe would provide some three dimensional discrimination within the ecliptic latitude. This relatively simple off-Earth probe could provide very high quality data to support the SCADM program, by transmitting both high resolution video data of the solar surface and such measurements of solar activity as particle, X-ray, ultraviolet, and radio emission fluxes. Topics covered include the orbit; constraints on the spacecraft; subsystems and their embodiments; optical imaging sensors and their operation; and the radiation-pressure attitude control system are described. The platform would be capable of mapping active regions on an hourly basis with one arc-second resolution.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 45-54
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  • 9
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    The corona and heliosphere (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The eleven-year solar cycle is an especially appropriate period over which to study the solar output and its variation, because during this cycle most of the important types of solar variability (many characterized by periods shorter than eleven years) are manifested. Studies of solar variability over a solar cycle will improve understanding of solar structure and of the generation of the solar wind, and this improved understanding can be useful in the related studies of stellar structure and stellar winds, since stellar observations are necessarily less detailed and sophisticated than are solar observations. A particularly significant benefit that will accrue from a thorough study of the solar atmosphere and its variability over the next solar cycle is a great enhancement in the usefulness of so-called 'proxy' data in studying longer term solar variations and their terrestrial implication.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 13-25
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  • 10
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    Solar coronal holes and cosmic ray intensity variations (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A relationship between the (North-South) asymmetry in the areas of the solar polar coronal holes and the (North-South) anisotropy in the cosmic ray intensity is examined. The investigation was extended over a period of two years, using ground based observations of coronal brightness obtained by the K-Coronameter. Periods for study of cosmic ray variations were chosen maximizing the asymmetry of the polar coronal holes. The importance of the role played by coronal holes in the solar modulation of galactic cosmic rays is emphasized.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; 11 p
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  • 11
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    An imaging X-ray spectrometer to study solar activity in conjunction with the SCADM program (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: An experiment is proposed to study solar active region dynamics and evolution. The experiment will employ an imaging X-ray spectrometer to study solar activity in conjunction with the SCADM program. A summary of the experiment is presented which includes the specifications and capabilities of the X-ray spectrometer, the scientific objectives, the method of approach, and a comparison of the experiment with other solar X-ray experiments. The experiment is proposed for use on the space shuttle due to its larger volume and weight capacity.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 245-258
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  • 12
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    The dependence of coronal hole size on large scale magnetic field strength (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The importance of mathematical models of the coronal structure for studies of coronal energetics, to simulate global flows of the solar wind, and to obtain reliable solar terrestrial predictions is discussed. Previous coronal models, including an example of a coronal MHD flow model, are reviewed. The development of a coronal model which is a logical extension of earlier models and which allows a closer relationship to the photospheric magnetic field as it is observed daily is described. The calculations are outlined. The assumptions of the model are: axisymmetric flow with no rotation, resulting in two dimensional flow in a meridional plane; zero viscosity and infinite electrical conductivity; polytropic, single fluid flow; and no momentum addition.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 209-217
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  • 13
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    Spatial evolution of magnetic fields as seen in coronal streamers to 12 R sub o during the solar cycle (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Outer coronal photographs made from high altitude aircraft at the solar eclipses of 1966, '70, '72, '73, and '79 which sample various times in the solar cycle are presented. Coronal streamers extending from the solar limb to 12 R sub o are displayed. The evolution of the streamers as they distort magnetic field lines to large distances from the Sun is examined. Results show that the distortion is varied, that the polar plumes can be traced beyond 8 R sub o, diverging apparently along dipole field lines, and that the divergence varies along the solar cycle. Various changes in nonpolar streamers are discussed including the tendency to become radial beyond 3 to 5 R sub o as if controlled by the solar wind.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 201-208
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  • 14
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    Observational requirements for measurements of solar rotation inward to the base of the convection zone (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Measurements of the rate of rotation at various depths in the solar interior and of temporal changes in the rotation are discussed. A technique to measure the absolute rate of the Sun's rotation (in meters per second) below its visible surface over the outer 3% of its radius using ground based equipment is described. The theory of the technique, developed to the base of the solar convection zone is analyzed. It is stressed that such deeper rotational measurements, extending from 3% inward to 25 to 30% of the Sun's radius can only be obtained from a spaceborne instrument which is not subject to the normal Earth based day-night observing cycle.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 159-173
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  • 15
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    Second generation detector for low order global solar oscillations (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The first observations of long period low order global solar oscillations grew out of diameter measurements made over an extended period of time. As a result of these investigations, a detailed understanding of the surface properties of the oscillations evolved, allowing development of a second generation detector. This new detector, currently under development directly utilizes various surface properties of the oscillations and does not, therefore, directly involve diameter measurements. The specifications of the detector, its supporting telescope and the observing program are reviewed.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 137-146
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  • 16
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    Problems of interior structure, the solar dynamo and the role of SCADM in providing interior diagnostics (1980)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: What is already known about the structure of the Sun, the motion of its convective zone, and the solar cycle is reviewed. Topics discussed include solar variability, solar 'seismology', velocity patterns, magnetic fields, and the dynamo theory. Observations are needed to determine global properties (solar luminosity and radius), oscillations (p and g models), velocities (variation of rotation with time and depth), and magnetic fields.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Study of the Solar Cycle from Space; p 55-64
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  • 17
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    Report on the Workshop on Intercomparison of Solar UV Irradiance Measurements and Related Instrument Calibration (1983)
    In:  Other Sources
    Details
    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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  • 18
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    Electrodynamic coupling in magnetically confined stellar X-ray loops (1983)
    In:  Other Sources
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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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  • 19
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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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  • 20
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    Dynamics of a surge observed in the C IV and H alpha lines (1983)
    In:  Other Sources
    Details
    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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  • 21
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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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  • 22
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    The stability of coronal loops - Finite-length and pressure-profile limits (1983)
    In:  Other Sources
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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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  • 23
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    Implications of high-energy neutron observations from solar flares (1983)
    In:  Other Sources
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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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  • 24
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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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  • 25
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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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  • 26
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    Determining the solar wind speed above active regions using remote radio-wave observations (1983)
    In:  Other Sources
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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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  • 27
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    Solar ultraviolet variability (1980)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: SOLAR PHYSICS
    Type: NASA, Washington Upper Atmosphere Res. Program; p 198
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  • 28
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    Physical conditions in the solar atmosphere above an active region (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: From a series of EUV spectra obtained at several heights above the limb in a solar active region, the volume emission measure is derived as a function of the electron temperature in the temperature range 70,000-1,500,000 K and the electron density at two locations. The emission measure from the coronal material (temperature greater than 700,000 K) is nearly the same everywhere and represents most of the material in the line of sight, while the emission measure from the transition region material (temperature between 70,000 and 250,000 K) fluctuates by two orders of magnitude from position to position above the active region. This is in agreement with the picture of this active region as consisting of a number of well-defined loops or lower portions of loops at transition region temperatures that are inhomogeneously distributed in much larger and more diffuse loop structures at coronal temperatures. The coronal data are in reasonable agreement with simple coronal models. Emission measures near 1,000,000 K evaluated using different ions differ by a factor of 4, suggesting difficulties with the atomic physics data.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 240
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  • 29
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    Morphology and spatial distribution of XUV and X-ray emissions in an active region observed from Skylab (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The morphology and spatial distribution of loops in an active region observed from Skylab are described. The active region loops were classified into hot loops with temperatures of 2 to 3 million K observed in coronal lines and X-rays, and cool loops with temperatures of 500,000 to one million K observed in transition zone lines. The brightest hot coronal loops in the active region are predominantly low-lying, compact, closely-packed, showing greater stability than the transition-zone loops, which are fewer in number, are large, and slender. The observed aspect ratio of the hot coronal loops in the range of 0.1 and 0.2 are almost two orders of magnitude larger than those of the Ne VII loops.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 67; Sept
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  • 30
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    Variation of the average 'freezing-in' temperature of oxygen ions with solar wind speed (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observations of the average oxygen ionization equilibrium as a function of speed of the solar wind are presented. At low solar wind speeds they indicate a coronal temperature at the freezing-in point of (1.6 + or - 0.2) x 10 to the 6th K. At speeds above 450 km/sec the apparent temperature starts to rise rapidly. This rise is tentatively interpreted in terms of a lack of thermodynamic equilibrium in the source region.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 7; Aug. 198
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  • 31
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    Average photospheric poloidal and toroidal magnetic field components near solar minimum (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: SOLAR PHYSICS
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  • 32
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    Observations of large fluxes of He/+/ in the solar wind following an interplanetary shock (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Los Alamos Scientific Laboratory instrumentation on Imp 7 has detected large fluxes of He(+) within that volume of solar wind plasma believed to be the solar ejecta driving the interplanetary shock wave disturbance of July 29, 1977. The very high He(+)/He(++) abundance ratio of 0.3 measured during this event suggests that this was solar prominence material only partially ionized by its passage through the corona.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 85; July 1
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  • 33
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    The low-frequency continuum as observed in the solar wind from ISEE 3 - Thermal electrostatic noise (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The low frequency continuum (LFC) noise between 30 and 200 kHz has been investigated from the ISEE 3 spacecraft in the solar wind by means of a radio astronomy experiment more sensitive than previously available. It is demonstrated that the LFC radiation observed in the solar wind is in the form of longitudinal plasma waves rather than transverse electromagnetic waves. The observed spectral characteristics are found to be a function of antenna length. In addition, both the absence of antenna spin modulation and the fact that these plasma waves do not propagate to large distances imply a local origin for the LFC.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 85; July 1
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  • 34
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    Physical properties of individual coronal loops in a solar active region observed in the XUV (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The physical properties of individual coronal loops in a solar active region observed in the XUV by the slitless objective grating spectroheliograph on board Skylab are investigated. Spectroheliograms of the normal active loop region McMath 12378 reveal three distinctive structural groups of loops in different temperature ranges, namely (1) small compact and smaller loops at temperatures of about 2,000,000 K observed in Fe XV and Fe XVI; (2) large Ne VII and Mg IX loops at temperatures from 500,000 to 1,000,000 K; and (3) chromospheric ribbons in He II and H alpha. The temperature of the active region is found to be uniform at about 2,000,000 K in the loops and background while loop density is found to be 3.5 x 10 to the 9th/cu cm in the loops and 2.5 x 10 to the 9th/cu cm in the surrounding background. Significant changes in the active region are observed in 24 h, although the gross temperature density structures of many loops do not show changes in 7 min. Gas pressure within the coronal loops is found to be about 40% greater than that of the background plasma. The observed loop parameters are noted to be consistent with flux-limited models of density enhancement in magnetic flux tubes and thus no esoteric heating function is required.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 238
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  • 35
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    Spatial distribution of XUV emission and density in a loop prominence (1980)
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    Publication Date: 2011-08-17
    Description: The spatial distribution of XUV emission in the 14 August, 1973 loop prominence observed with the NRL spectroheliograph on Skylab is studied. The loop prominence consists of two large loops and is observed in lines from ions with temperatures ranging from 50,000 to 3,000,000 K. The loops seen in low temperature lines such as from He II, Ne VII, Mg VII, Mg VIII, and Si VIII are systematically displaced from loops seen in higher temperature lines such as from Si XII, Fe XV, and Fe XVI. The cross section of the loop, particularly in cooler lines is nearly constant along the loop. For hotter loops in Si XII, Fe XV, and Fe XVI, however, emission at the top of the loop is more intense and extended than that near the footpoints, which makes the loops appear wider at the top. The observed spatial displacement between cooler and hotter loops suggest that the 14 August loop prominence is composed of many magnetic flux tubes, each with its own temperature.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 65; Mar. 198
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  • 36
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    Evolution of solar magnetic fields - A new approach to MHD initial-boundary value problems by the method of nearcharacteristics (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A method of analysis for the MHD initial-boundary problem is presented in which the model's formulation is based on the method of nearcharacteristics developed by Werner (1968) and modified by Shin and Kot (1978). With this method, the physical causality relationship can be traced from the perturbation to the response as in the method of characteristics, while achieving the advantage of a considerable reduction in mathematical procedures. The method offers the advantage of examining not only the evolution of nonforce free fields, but also the changes of physical conditions in the atmosphere accompanying the evolution of magnetic fields. The physical validity of the method is demonstrated with examples, and their significance in interpreting observations is discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 240
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  • 37
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    Giant solar flares in Antarctic ice (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A new hypothesis proposes an explanation for the presence of four prominent spikes in a long time record of the NO3(-) concentration inside the Antarctic ice. This solar flare hypothesis suggests that the ionizing radiation necessary in the spike formation could have come from extremely powerful solar flares. It is proposed that these flares would have occurred during the times of the largest maxima in the solar cycle. The solar flare hypothesis is compared with the supernova hypothesis.
    Keywords: SOLAR PHYSICS
    Type: Nature; 287; Sept. 25
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  • 38
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    High-resolution X-ray spectra of solar flares. III - General spectral properties of X1-X5 type flares (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: High-resolution X-ray spectra of six class X1-X5 solar flares are discussed. The spectra were recorded by spaceborne Bragg crystal spectrometers in the ranges 1.82-1.97, 2.98-3.07 and 3.14-3.24 A. Electron temperatures derived from dielectronic satellite line to resonance line ratios for Fe XXV and Ca XIX are found to remain fairly constant around 22,000,000 and 16,000,000 K respectively during the rise phase of the flares, then decrease by approximately 6,000,000 K during the decay phase. Nonthermal motions derived from line widths for the April 27, 1979 event are found to be greatest during the rise phase (approximately 130 km/sec) and decrease to about 60 km/sec during decay. Volume emission measures for Fe XXV, Ca XIX and Ca XX are derived from photon fluxes as a function of temperature, and examination of the intensity behavior of the Fe K alpha emission as a function of time indicates that it is a result of fluorescence. Differences between the present and previous observations of temperature variation are discussed, and it is concluded that the flare plasmas are close to ionization equilibrium for the flares investigated.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 239
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  • 39
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    Quantitative representation of nonrepetitive temporal behavior (1980)
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    Publication Date: 2011-08-17
    Description: Analytical representations suitable to analyze the nonrepetitive pulse-like temporal behavior of physical quantities are derived. The representation utilizes solutions of a linear model equation in which the temporal variation is subject to time-dependent driving and dissipative forces. The property of solutions is described, and it is shown that such representations can provide a basis for quantitative comparisons of behaviors and a basis for physically meaningful interpretations of the results. Observations of solar flares in the soft X-ray flux have been analyzed with this method.
    Keywords: SOLAR PHYSICS
    Type: Physics of Fluids; 23; July 198
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  • 40
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    Atomic data for S IV and solar observations of the 3x/2/3p /2/P-3s3p/2/ /4/P multiplet (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: High resolution observations of intersystem lines of S IV near 1400 A are available from Skylab. These lines are potentially useful as density diagnostics for the solar atmosphere. Energy levels, transition probabilities and collision strengths have, therefore, been calculated for S IV, including the configurations 3x(2)3p, 3s3p(2), and 3s(2)3d. Line intensities and level populations have been calculated as a function of electron density. The calculated population of the 3s3p(2) (4)P(5/2) level is found to reach a pseudo-Boltzmann equilibrium at a density which is four times higher than is inferred from solar spectra and level population calculations of lighter ions such as O IV.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 86; 1-2,; June 198
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  • 41
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    The coronal spectra of Fe XV and Ni XVII (1980)
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    Publication Date: 2011-08-17
    Description: Predicted allowed and forbidden EUV line intensities of Fe XV and Ni XVII are presented in explicit graphical form, clarifying and extending the earlier treatment of Bely and Blaha (1968). In the case of the former ion a detailed comparison with available observations leads to questioning or rejection of some presently accepted line identifications (323.57 A, 317.61 A), and on the other hand suggests that a quiet sun line at 304.853 A is due to Fe XV. For the little known ion Ni XVII estimates of level structure and line wavelengths are given and a preliminary comparison is made with recent flare observations.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 65; Feb. 198
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  • 42
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    An empirical polytrope law for solar wind thermal electrons between 0.45 and 4.76 AU - Voyager 2 and Mariner 10 (1980)
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    Publication Date: 2011-08-18
    Description: In this paper empirical evidence is presented that between 0.4 and 5 AU the thermal portion (but not all) of the solar wind electron population obeys a polytrope relation. It is also shown that this functional relationship is a member of a broader class of possible laws required of a steady state, fully ionized plasma whose proper frame electric field is dominated by the polarization electric field. The empirically determined, thermodynamically interesting value of the polytrope index (1.175) is virtually that predicted (1.16) by the theoretical considerations of Scudder and Olbert (1979). Strong, direct, empirical evidence for the nearly isothermal behavior of solar wind electrons as has been indirectly argued in the literature for some time is provided.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 85; Oct. 1
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  • 43
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    Hydromagnetic wavelike phenomena from Helios time delay measurements by remote sensing (1980)
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    Publication Date: 2011-08-17
    Description: A survey of the electron content measurements during solar occultations of the Helios A and B spacecraft is presented, and a spectral analysis using the method of maximum entropy is discussed. Typical variations measured are on the order of 0.1-1.8 x 10 to the 18th/sq m, while typical values for the rate of change are 0.7-50 x 10 to the 13th per sq m per sec. Numerical results in agreement with findings from Helios radio science, reveal a fundamental period of about 70 minutes superimposed by minor spectral peaks corresponding to shorter time periods such as 35 and 25 minutes. In addition, the periodicities observed in electron content are discussed in terms of fast hydromagnetic waves excited by nonlinear Alfven waves via coupling terms before crossing the Helios ray path. It is noted that for the first time experimental evidence is presented that hydromagnetic waves may actually be propagating from the solar corona into the interplanetary medium.
    Keywords: SOLAR PHYSICS
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  • 44
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    Microscale instabilities in stream interaction regions (1980)
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    Publication Date: 2011-08-17
    Description: A theoretical investigation of the microstructure of solar wind stream interaction regions is presented. The role of several electrostatic kinetic instabilities is discussed which may be important within the stream interface and the compression region. Inside of 1 AU the interface is likely to be stable against the electrostatic streaming instabilities considered. Between 1 and 2 AU it is argued that the interface will excite the magnetized ion-ion instability. The compression region is also found to be unstable beyond 1 AU, where the modified two-stream instability, beam-cyclotron instability, and ion-acoustic instability will be important in determining the structure of the compressive pulses as they evolve into forward and reverse shocks. It is concluded that the modified two-stream instability and beam-cyclotron instability predominately play a role in heating the electrons to the threshold for the ion-acoustic instability.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 85; Feb. 1
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  • 45
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    A three-dimensional model of corotating streams in the solar wind. II - Hydrodynamic streams (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Theoretical aspects of corotating solar wind dynamics on a global scale are examined by means of numerical simulations executed with a nonlinear, inviscid, adiabatic, single fluid, three-dimensional hydrodynamic formulation. The factors most strongly affecting stream evolution, namely, the intrinsic correlations among density, temperature, and velocity existing near the source, the amplitude, longitudinal breadth and latitudinal breadth of the stream, and the heliographic latitude of the centroid of the stream, are considered. Calculations indicate that even in the presence of substantial meridional gradients, the latitudinal transport of mass, energy, and momentum by streams appears to have little impact on the overall evolution of the structure.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 85; Feb. 1
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  • 46
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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.
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  • 47
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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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  • 48
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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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  • 49
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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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  • 50
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    The solar O III spectrum. II - Longer wavelengths, line widths, and the He II Lyman alpha radiation field (1983)
    In:  Other Sources
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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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    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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  • 52
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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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  • 53
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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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  • 54
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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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  • 55
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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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  • 56
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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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  • 57
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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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  • 58
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    Microwave and hard X-ray observations of a solar flare with a time resolution better than 100 ms (1983)
    In:  Other Sources
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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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  • 59
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    The isotopic composition of solar flare noble gases (1983)
    In:  Other Sources
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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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  • 60
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    High-resolution X-ray spectra of solar flares. IV - General spectral properties of M type flares (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The spectral characteristics in selected narrow regions of the X-ray spectrum of class M solar flares are analyzed. High-resolution spectra in the ranges 1.82-1.97, 2.98-3.07, 3.14-3.24 and 8.26-8.53 A, which contain lines important for the determination of electron temperature and departure from ionization equilibrium, were recorded by spaceborne Bragg crystal spectrometers. Temperatures of up to 20,000,000 K are obtained from line ratios during flare rise phases in M as well as X flares, while in the decay phase the calcium temperature can be as low as 8,000,000 K, which is significantly lower than in X flares. Large nonthermal motions (on the order of 130 km/sec at most) are also observed in M as well as X flares, which are largest during the soft X-ray rise phase. Finally, it is shown that the method proposed by Gabriel and Phillips (1979) for detecting departures of electrons from Maxwellian velocity distributions is not sufficiently sensitive to give reliable results for the present data.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 241
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  • 61
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    Observations of a probable change in the solar radius between 1715 and 1979 (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A decrease in the solar radius is determined using the technique of Dunham and Dunham (1973), in which timed observations are made just inside the path edges. When the method is applied to the solar eclipses of 1715, 1976, and 1979, the solar radius for 1715 is 0.34 + or - 0.2 arc second larger than the recent values, with no significant change between 1976 and 1979. The duration of totality is examined as a function of distance from the edges of the path. Corrections to the radius of the sun derived from observations of the 1976 and 1979 eclipses by the International Occultation Timing Association are also presented.
    Keywords: SOLAR PHYSICS
    Type: Science; 210; Dec. 12
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  • 62
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    Solar gravitational redshift (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Wavelengths of solar spectrum lines should be shifted toward the red by the sun's gravitational field as predicted by metric theories of gravity according to the principle of equivalence. Photographic wavelengths of 738 solar Fe I lines and their corresponding laboratory wavelengths have been studied. The measured solar wavelength minus the laboratory wavelength averaged for the strong lines agrees well with the theoretically predicted shift. Studies show that the departures depend on line strength. No dependence of the departures on wavelength was found within the existing data. By studying strong lines over a wide spectral range, velocity shifts caused by the complex motions in the solar atmosphere seem to affect the results in a minimal fashion.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 66; June 198
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  • 63
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    The equatorial rotation rate of the supergranulation cells (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The equatorial rotation rate of the supergranulation cells has been observed to be 14.72 plus or minus 0.07 deg/day. Velocity patterns observed at different times are cross-correlated to derive the rotation rate. The observed rate is 3% faster than recent observations of the surface rotation rate by Doppler shifts. The difference between the cell rate and surface rate is consistent with a model of the supergranular convection in which angular momentum per unit mass is conserved in the radial flow (Foukal, 1977).
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 66; June 198
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  • 64
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    Observations of the O I 1355.6 A and C I 1355.8 A lines in solar flares (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper presents observations of the intersystem line O I 1355.6 A and the allowed line C I 1355.8 A in solar flares. In flares, the intersystem O I line is weaker than the allowed C I line and the intensity ratio O I/C I is 0.3-0.7. On the other hand, in active regions, O I line is stronger than the C I line and O I/C I is about 1-2, while in quiet sun regions, the O I line is much stronger than the C I line and O I/C I not in excess of 20. The variation of the intensity ratio from quiet sun region to flares may be due to an electron density enhancement of a factor of about 50 in flares.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 86; 3, Ju; June 198
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  • 65
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    The titanium oxide phi system (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The phy system of titanium oxide has been studied in emission in the near-infrared, with the Fourier transform spectrometer at a resolution of 8000,000. Approximately 3000 lines from 25 bands of this system have been identified, including all five 0-0 and 0-1 bands corresponding to the five natural titanium isotopes. Eleven vibrational levels have been observed, and all bands have been rotationally analyzed. Band intensities are agreement with known isotopic abundances and calculated Franck-Condon factors.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal SupplementSeries; 42; Feb. 198
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  • 66
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    Dynamics of flare sprays (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: During solar cycle No. 20 new insight into the flare-spray phenomenon has been attained due to several innovations in solar optical-observing techniques (higher spatial resolution cinema-photography, tunable passband filters, multislit spectroscopy and extended angular field coronagraphs). From combined analysis of 13 well-observed sprays which occurred between 1969-1974 it is concluded that (1) the spray material originates from a preexisting active region filament which undergoes increased absorption some tens of minutes prior to the abrupt chromospheric brightening at the 'flare-start', and (2) the spray material is confined within a steadily expanding, loop-shaped (presumable magnetically controlled) envelope with part of the materials draining back down along one or both legs of the loop.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 65; Mar. 198
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  • 67
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    Densities and mass motions in transition-zone plasmas in solar flares observed from Skylab (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The electron densities and bulk motions in the transition-zone plasma of a solar flare are investigated by an analysis of EUV emission line spectra taken on Skylab. Spectra of three flares were obtained with the NRL normal incidence grating slit spectrograph in the ranges 1100-1940 and 1940-3940 A. The line ratios of transition-zone Si III lines and the intensity of the forbidden O IV 1401-A lines during flare maximum indicate electron densities on the order of 10 to the 12th/cu cm, decreasing by a factor of 2 to 3 in the flare decay phase. Line broadening of the transition-zone ions such as Si III, O IV, C IV and N V is noted, and the observed asymmetrical N V line profiles are approximated by a bi-Gaussian model of a stationary and a moving plasma component with a bulk velocity of 12 to 70 km/sec. Turbulent velocities of from 45 to 85 km/sec and from 20 to 40 km/sec are also indicated for the moving and stationary components of the transition-zone plasma, respectively.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 65; Mar. 198
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  • 68
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    Solar limb emission lines near Ca II H & K and their spatial intensity variations (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper employs solar observations of high spatial and spectral resolution to identify emission lines seen in the extended wings of Ca II H & K near the solar limb. Emission lines in the wings of H & K represent valuable diagnostics of the atmospheres of cool stars, with a varying information content which depends on their particular formation mechanism. In solar spectrograms different emission line formation mechanisms can be distinguished by the character of the spatial intensity variation (SIV) apparent in the lines. Various classes of H & K emission features, their spatial intensity variations and their formation mechanisms (of which some pose further problems) are discussed. A new extended list of line identifications is compiled based on their formation class and compared with other line lists. Evidence is found that stellar luminosity-sensitive lines tend to show large spatial intensity variation on the sun.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics Supplement Series; 39; Mar. 198
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  • 69
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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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  • 70
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    Observation of chromospheric evaporation during the Solar Maximum Mission (1983)
    In:  Other Sources
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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
    Type: (ISSN 0038-0938)
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  • 71
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    Conductive flux in the chromosphere derived from line linear polarization observation (1983)
    In:  Other Sources
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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
    Type: (ISSN 0038-0938)
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  • 72
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    Radio blips and hard X-rays in solar flares (1983)
    In:  Other Sources
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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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  • 73
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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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  • 74
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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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  • 75
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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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  • 76
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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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  • 77
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    Effects of core perturbations on the structure of the sun (1983)
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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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  • 78
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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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  • 79
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    Lines of Fe XII sensitive to coronal electron density (1983)
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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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  • 80
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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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  • 81
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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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  • 82
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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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  • 83
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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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  • 84
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    Heliospheric magnetic fields and plasmas (1983)
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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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  • 85
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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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  • 86
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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
    Details
    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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  • 87
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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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  • 88
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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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  • 89
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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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  • 90
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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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  • 91
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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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  • 92
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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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  • 93
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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
    Details
    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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  • 94
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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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  • 95
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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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  • 96
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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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  • 97
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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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  • 98
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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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  • 99
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    On the field configuration in magnetic clouds (1983)
    In:  CASI
    Details
    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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  • 100
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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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