bluuebunny/crossref_metadata_2025_split huggingface dataset:
Masked Coronal Mass Ejections: An Attempt to Demask Them
Authors: Filippov M. , Golbraikh E. , Steinitz R. 
Published: July 2016

AbstractWe unify the elaborated classification system applied to Coronal Mass Ejections (CME). The unification is possible due to the fact that one and the same phenomenon – i.e., mass ejection – is projected on the plane of the sky. We conclude that it is not necessary to keep ten different morphological classes of CME’s, when they represent only one and the same phenomenon, seen in different aspects. Simpler future model of CME origin can be based on the suggested approach.
Phenomenological Pattern of the Outer Solar Corona Structure
Authors: Gulyaev R. A. 
Published: July 2016

AbstractTopology of the outer solar corona has been analysed. In doing so the outer corona is treated as a visible manifestation of the heliospheric current sheet base. Generalization of the recent conception of the flat (galaxy-like) solar corona has been suggested. It is shown that 3D structure of the outer corona is well fitted by a second-degree surface of a hyperbolic paraboloid.
Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare
Authors: Karlický M. , Hénoux J. C. 
Published: July 2016

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.
Contrast of Filament Bright Rims
Authors: Kononovich E. V. , Smirnova O. B. , Heinzel P. , Kotrč P. 
Published: July 2016

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.
Modelling the Electron Density Distribution in the July 1991 Solar Corona
Authors: Clette F. , Cugnon P. , Gabryl J.-R. 
Published: July 2016

AbstractUsing intensity and polarization maps computed from white-light observations of the July 11, 1991 solar eclipse, we present axisymmetrical models of the large-scale electron density distribution in the corona. These models are based on an expansion in Legendre polynomials, and are flexible enough to fit individual features, like streamers and holes. Furthermore, as the symmetry axis of our models can take any orientation, we consider two plausible configurations, aligned on the rotation axis or the mean bipolar magnetic field axis. Their respective abilities to reproduce a strongly non-spherical global magnetic structure are then compared.
The White-Light and Emission Coronae at the July 22, 1990 Eclipse
Authors: Rušin V. , Marková E. 
Published: July 2016

AbstractVarious instruments were used to study the solar corona at the July 22, 1990 eclipse. The white-light corona of July 22, 1990 is of maximum type (the Ludendorff index of the corona’s shape turns out to be a+b = 0.04). There are many streamers nearly equally distributed around the whole Sun, except of the southwest region where large coronal hole was located. The green (530.3 nm) and red (637.4 nm) coronal line intensities display many rapid changes in active regions around the eclipse day. Huge prominences were located above the E-limb. The estimated total brightness of the white-light corona (WLC) reached its value ofJK= 1.32 × 10−6.
SOHO Science Opportunities
Authors: Fleck B. , Domingo V. , Poland A. I. 
Published: July 2016

AbstractThe space-based Solar and Heliospheric Observatory (SOHO) is a joint venture of ESA and NASA within the frame of the Solar Terrestrial Science Programme (STSP), the first ”Cornerstone“ of ESA’s long-term programme ”Space Science — Horizon 2000“. The principal scientific objectives of the SOHO mission are: a) a better understanding of the structure and dynamics of the solar interior using techniques of helioseismology, and b) a better insight into the physical processes that form and heat the Sun’s corona, maintain it and give rise to its acceleration into the solar wind. To achieve these goals, SOHO carries a payload consisting of 12 sets of complementary instruments which are briefly described here.
SOHO Operations
Authors: Fleck B. , Domingo V. , Poland A. I. 
Published: July 2016

AbstractSOHO, the Solar and Heliospheric Observatory, is currently scheduled for launch in 1995. After launch SOHO will be operated from the Experiment Operations Facility (EOF) at Goddard Space Flight Center (GSFC). The EOF will consist of facilities for instrument commanding, data reception, data reduction and data analysis. This paper briefly describes the operations concepts.
‘Sumer’ – Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm K. , Curdt W. , Gabriel A. H. , Grewing M. , Huber M. C. E. , Jordan S. D. , Kühne M. , Lemaire P. , Marsch E. , Poland A. I. , Schühle U. , Thomas R. J. , Timothy J. G. , Vial J.-C. 
Published: July 2016

AbstractThe experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of extreme ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy; provide stigmatic images of selected areas of the Sun in the EUV with high spatial, temporal and spectral resolution and obtain full images of the Sun and the inner corona in selectable EUV lines, corresponding to a temperature range from 104to more than 1.8 x 106K. The spatial and spectral resolution capabilities of the instrument will be considered in this contribution in some detail, and a new detector concept will be introduced.
Equation of state of dense Hydrogen and the plasma phase transition; A microscopic calculational model for complex fluids
Authors: Perrot F. , Dharma-Wardana C. 
Published: July 2016

AbstractWe discuss problems related to the electronic and ionic structure of fluid Hydrogen, for equation of state calculations in the domain where a ”plasma phase transition” (PPT) may occur. It is argued that the ionization of an electron bound to a particular nucleus proceeds through a progressive derealization involving ”hopping” electron states (i.e. cluster states). A description of the plasma containing pseudoatoms, pseudomolecules and free electrons is proposed. The PPT, if it exists, might be a mobility edge transition across a percolation threshold. It is shown how the effect of electron density, field-particle distributions and temperature on the binding energy of these pseudoatoms and pseudomolecules, can be included. Finally the abundances of these objects is determined by a minimization which allows the self-consistent optimization of ionic as well as electronic parameters contributing to the total free energy.
Jovian seismology
Authors: Mosser Benoît 
Published: July 2016

AbstractThis paper reviews a new astrophysical subject: seismology of the giant planets. Seismology is dedicated to the sounding of the interior structure of any object; on the other hand, the interiors of the Jovian planets need to be constrained, in order to improve our knowledge of their structure and of their evolution, as well as the thermodynamical laws involved at high pressures and low temperatures. The relationship between Jovian seismology and, first, Jovian internal structure, and second, high pressure physics, is examined, in order to determine the task of “dioseismology”† in the next years. We present then the seismological theoretical approaches developped since the pionnering work of Vorontsov et al. (1976), who calculated the frequencies of the Jovian eigenmodes. We report the first observational attempts for the detection of the oscillations of Jupiter. We discuss the observational results and examine what can be done in the future.
Hipparcos
Authors: Baglin A. , Fernandes J. 
Published: July 2016

AbstractThe HIPPARCOS mission will permit a decisive step forward in the comparison between observed and predicted global properties of stars, in producing distances and apparent magitudes with accuracies more than one order of magnitude higher than before. Nearby stars of intermediate and low mass will allow for statistical tests on the validity of the equation of state, like for instance the steepness of the main sequence.
On Radiative Transfer Near the Plasma Frequency at Strong Coupling
Authors: Kurilenkov Yu. K. , Van Horn H.M. 
Published: July 2016

AbstractThe effects of strong coupling on the frequency-averaged optical characteristics of plasmas, such as the Rosseland mean-free-path, are considered. The general expression for the Rosseland mean opacity has been analyzed in terms of the transverse dielectric function of a dense plasma and the frequency-dependent effective collision frequency. The corresponding values of the absorption coefficient and the refractive index for a dense plasma are presented at ω ≤ ωp up in obvious forms.
Non-Polar Variation of Latitude
Authors: Yumi S. 
Published: July 2016

ABSTRACTAnalysing the residual latitude of the station, local trend in latitude variation other than by the polar motion was found.Residual latitude was calculated for each of 26 stations which gave the continuous records of observation during 6 years comprising — 1962 — 1967 as a difference between observed variation of latitude and – normal variation calculated by the polar coordinates Iderived from all the results of 26 stations.As far as the results during these six years are concerned, local trend at any station it seemed to be expressed in terms of 3λ.Assumed effect of local trend on the coordinates values of the instantaneous pole is also discussed.
Rotation and Macroturbulence in Supergiant Stars
Authors: Rosendhal Jeffrey D. 
Published: July 2016

AbstractA statistical investigation has been made of rotation and macroturbulence in early type la and lab supergiants. The principal results are: (1) At all spectral types in the range B0-A5 both rotation and macroturbulence contribute to the observed line broadening. In the early B stars rotation is as important a broadening agent as large-scale mass motion. In the middle B and A stars turbulence dominates but there still is an appreciable contribution from rotation. (2) In spite of the fact that the stars observed seem to be losing mass, there is no strong evidence for significant angular momentum loss.
The Light Variation and the Orbital Elements of AM Leonis = ADS 8024 A
Authors: Binnendijk L. 
Published: July 2016

AbstractThe star was followed photoelectrically in two colors through five consecutive nights in 1968 at Kitt Peak National Observatory. The light of the fainter visual component (a physical companion) was excluded. At primary minimum the system undergoes a total eclipse lasting 25 min. New internally consistent elements have been derived. A subluminous region on the larger star can be located. The previous light curve by Abrami leads to the same geometrical elements but to different photometric elements even when freed from the light of the distant companion.The paper appeared inAstron. J.74, 1031 (1969).
Some Results on A.G.K. 2 – A.G.K. 3
Authors: Lacroute P. , Valbousquet A. 
Published: July 2016

Thanks to W. Dieckvoss’s great obligingness who communicated to us all his results, we could apply the overlap method to the A.G.K. 2 -A.G.K. 3.Some studies are given in (1) and (2) on the use of overlapping in A.G.K. 2 – A.G.K. 3; here only qualities of the results are studied from the pole to +40° of declination. Moreover some results will be improved by new measures. The details of the method will be published later.
The Planetary Masses and the Orbits of the First Four Minor Planets
Authors: Schubart J. 
Published: July 2016

AbstractNumerical tests are the basis of a study about the effects caused in the orbits of the planets (l)-(4) by possible errors in the system of planetary masses. The masses of five major and three minor planets are considered. Especially, the effects caused by (1) Ceres in the orbit of (2) Pallas since the time of discovery are found to be large enough for a determination of the mass of Ceres. A first result for this mass is (6.7 ±0.4) x 10-10 solar masses.
Corrections to the Lunisolar Precession and the Motion of the Equinox from Proper Motions of Cepheids
Authors: Sinzi A.M. 
Published: July 2016

AbstractCorrections to Newcomb’s lunisolar precession and to motion of the equinox are evaluated from proper motions of 77 Cepheids, employing recently determined values of their distances. Results are diverse, depending on the weighting method. If the effect of the cosmic dispersion is neglected and ω0 is imposed to be 25 km/s/kpc, then Δp1 = 1.″1 ±0.″2 and Δλ′ + Δe = 1.″0 ±0.″1 per century in the FK4 system.
Relaxation Times in Strictly Disk Systems
Authors: Rybicki George B. 
Published: July 2016

AbstractIt is shown that the time of relaxation by particle encounters of self-gravitating systems in the plane interacting by 1/r2 forces is of the same order of magnitude as the mean orbit time. Therefore such a system does not have a Vlasov limit for large numbers of particles, unless appeal is made to some non-zero thickness of the disk. The relevance of this result to numerical experiments on galactic structure is discussed.
Area-Weighting of Sunspot Group Positions and Proper Motion Artifacts
Authors: Petrovay K. 
Published: July 2016

AbstractTwo simple examples are presented to show that concepts about the physical nature of sunspot groups may significantly influence the statistical data analysis process. In particular, the second example shows that the well-known difference in the decay rates of preceding (p-) and following (f-) polarity parts of sunspot groups may lead to a fake proper motion effect when area-weighted group positions are used. This effect may be responsible for some recent contradictory findings concerning the motions of sunspot groups. It is therefore argued that while area-weighting is adequate when calculating the mean positions of p- and f-parts of a sunspot group separately, defining the position of the group as a whole by the unweighted average of the mean positions of the p- and f-parts is more satisfactory from the theoretical point of view (whenever it is possible to distinguish between spots of different polarities). Similarly, it is best not to “correct” sunspot proper motions for internal differential rotation within groups.
The Application of Boundary Element Method to 3-D Solar Linear Force-Free Magnetic Fields
Authors: Yan Yihua , Yu Qing , Kang Feng 
Published: July 2016

AbstractIn this paper a 3-d formulation is applied to extrapolate the solar magnetic field from the measured magnetogram directly, and no additional data treatment is needed. The validity of the proposed formulation is demonstrated by comparison between calculated and analytical or observed results of some magnetic force-free field problems.
Early Results from the HAO/NSO Advanced Stokes Polarimeter
Authors: Lites B. W. , Elmore D. F. , Tomczyk S. , Seagraves P. , Skumanich A. , Streander K. V. 
Published: July 2016

AbstractThe Advanced Stokes Polarimeter is a new instrument dedicated to quantitative measurement of vector magnetic fields in lines formed at several heights in the solar atmosphere at high angular resolution. We present results for a small, symmetric sunspot observed under good seeing conditions near disk center on 25 March 1992. The narrow penumbral “spines” of more vertical field reported by Degenhardt and Wiehr (1991) and Title et al. (1992) are clearly seen in these observations. These spines are characterized by higher field strength than the surrounding penumbra. The inferred field azimuth indicates that these spines flare out with height, as would be expected of stronger field intrusions within the background penumbral field. The observations indicate the penumbral field “canopy” extends well beyond the outer edge of the penumbra. Outside of the sunspot, the small flux elements of mixed polarity are nearly vertical in orientation.
Strong and Weak Magnetic Fields: Nature of the Small-Scale Flux Elements
Authors: Stenflo Jan Olof 
Published: July 2016

AbstractThe 20 year old conclusion that more than 90% of the magnetic flux recorded by magnetographs in quiet and active regions is in strong-field, kG form has recently been supported by direct observations of Zeeman splitting in the infrared (near 1.6 μm). The magnetic and thermodynamic properties of the kG fluxtubes have been explored in considerable detail over the past decade, in particular through Fourier transform spectrometer observations combined with Stokes inversion procedures. The weak fields have proven to be much more elusive, and it was not until last year that the first definite identifications of intrinsically weak (less than kG) fields in the low photosphere could be made, using the Stokes V profiles of an infrared line pair.
Coronal Magnetic Fields Deduced from Radio Methods
Authors: Krüger A. , Hildebrandt J. 
Published: July 2016

AbstractMajor problems of the physics of the solar atmosphere and processes of solar activity are due to the poor knowledge of the magnetic fields outside the photosphere. Unique methods to determine magnetic fields in the corona and chromosphere make use of radio observations in close connection with information obtained in other spectral ranges e.g. the optical and X-ray regions. Based on relevant emission and propagation processes, the basic radio methods providing information on the parent magnetic fields are summarized. Signatures in the microwave and meter wave regions are used to derive magnetic field parameters at different levels in the solar atmosphere of active regions during quiet and flaring conditions. Implications on fine and gross structures are briefly discussed and consequences on acting physical processes mentioned.
Evolving Features of Hβ Doppler Velocity Fields at Sites of Flares
Authors: Li Wei , Ai Guoxiang , Zhang Hongqi 
Published: July 2016

AbstractWe analyzed eight active regions with more than 600 flare kernels and ribbons, and relevant time sequence Hβ chromospheric Dopplergrams. These data showed that during several hours prior to the flares, the velocity field evolves so that the sites of the flare kernels and ribbons become close to the inversion line of the velocity field. This result holds regardless of whether or not the flare sites are wholly located in blue-shifted areas, or are far from the the inversion line of the line-of-sight velocity field, or are partly within red-shifted areas.
Microwave Emission from a Sunspot III. Implications for the Force Balance in a Static Sunspot
Authors: Lee Jeongwoo W. , Gary Dale E. , Hurford G.J. , Zirin H. 
Published: July 2016

AbstractWe present our earlier measurement of the coronal fields above a sunspot in the active region, NOAA #4741, which was obtained using microwave spectroscopy from the Owens Valley Radio Observatory (OVRO) in a form that allows comparison with theoretical models. Our empirical results for the coronal fields are compared with several theoretical models in order to understand the magnetic structure of a static sunspot. It is found that the presence of transverse pressure gradients should be considered to get a satisfactory fit.
Magnetic Field Configuration in Hα Flare Loops and Flaring Arches
Authors: Bhatnagar Arvind , Srivastava Nandita 
Published: July 2016

AbstractIt is concluded from the observations of Hα flaring loops and flaring arches that these are two entirely different phenomena. From the reconstructed shape of flaring loops, it is suggested that the magnetic field lines revert to potential field configuration from sheared non-potential state.
Pre-Eruption Disturbance of an Active Filament
Authors: Wang Jingxiu , Shi Zhongxian 
Published: July 2016

AbstractA pre-eruption disturbance of an active filament has been observed. The disturbance is characterized by untwisting rotation and vigorous upward motion. It starts at the site where microflares took place, and appears in the late phase of magnetic flux cancellation beneath the central part of the filament, when more than 1020 Mx flux had disappeared.
The Proton Flare and Evolution of Magnetic Fields in a Decaying Active Region
Authors: Zhang Guiqing 
Published: July 2016

AbstractIn this paper, the evolution history of longitudinal magnetic field of a decaying active region (NOAA AR6703) was studied. We also described the X1.9/4B flare occurring in AR6703, as well as the accompaning events, and emphasized in analysizing the features of longitudinal magnetic fields before the flare.
Model Predictions for Magnetic Shear Changes During Solar Flares
Authors: Forbes T.G. 
Published: July 2016

AbstractMagnetic shear is sometimes defined observationally as the rotation of the photospheric vector magnetic field away from the field direction of a corresponding potential state. It is often assumed that the observational shear is a direct measure of the energy stored in coronal currents. However, this is not true in general as is illustrated here by considering the changes in observational shear in a variety of flare models. Some of these models predict rotations in the photospheric transverse field which are too small to be detected by present day instruments, but other models predict relatively large rotations in highly localized regions. In principle, observations of the transverse field might confirm or eliminate models in the latter group.
The Dynamic Evolutionary Processes of the Magnetic Fields in the Solar Active Region Boulder 5395
Authors: Liu Xin Ping , Zhang Hong Qi , Lin Jing , Liu Gui Lin 
Published: July 2016

AbstractIn this paper, based on observational information we proposed an opening bipolar magnetic field model and studied numerically the dynamic evolutionary processes of the magnetic fields by solving a complete set of MHD equations. The aim is to discuss one of the mechanisms of energy build up of solar flares produced in the active region Boulder 5395.