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  • Other Sources  (9)
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  • 1
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    Radiation transfer through a model sunspot (1979)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A cylindrically symmetric model for a sunspot atmosphere using the similarity principle of Schlueter and Temesvary for the magnetic field configuration is presented. The equations of magnetostatic equilibrium are used, augmented by a radial Evershed flow. The LTE radiative transfer equations for the Stokes vector were solved under a variety of conditions for a ray emerging from a typical penumbral point. The contribution from isolated lines to the broadband circular polarization in sunspot penumbrae is evaluated using a more realistic model sunspot atmosphere than has hitherto been considered. Results indicate that the inclusion of a velocity field along the magnetic field vector is unable to give a net circular polarization of sufficient magnitude, although the variation with the angle between the line-of-sight and the magnetic field vector is in qualitative agreement with observations. The corresponding results for the net linear polarization are satisfactory.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 63; Sept
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  • 2
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    The polarization of continuum radiation in sunspots. I - Rayleigh and Thomson scattering (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Expressions are derived for the Stokes parameters of light scattered by a layer of free electrons and hydrogen atoms in a sunspot. A physically reasonable sunspot model was found so that the direction of the calculated linear polarization agrees reasonably with observations. The magnitude of the calculated values of the linear polarization agrees generally with values observed in the continuum at 5830 A. Circular polarization in the continuum also accompanies electron scattering in spot regions; however for commonly accepted values of the longitudinal magnetic field, the predicted circular polarization is much smaller than observed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 39; Nov. 197
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  • 3
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    Non-LTE profiles of the Al I autoionization lines (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A non-LTE formulation is given for the transfer of radiation in the autoionizing lines of neutral aluminum at 1932 and 1936 A through both the Bilderberg and Harvard-Smithsonian model atmospheres. Numerical solutions for the common source function of these lines and their theoretical line profiles are calculated and compared with the corresponding LTE profiles. The results show that the non-LTE profiles provide a better match with the observations. They also indicate that the continuous opacity of the standard solar models should be increased in this wavelength region if the center-limb variations of observed and theoretical profiles of these lines are to be in reasonable agreement.
    Keywords: SPACE SCIENCES
    Type: Solar Physics; 34; Jan. 197
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  • 4
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    Studies in spectral line formation. IV - Singly ionized calcium (1971)
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    Publication Date: 2019-06-27
    Description: Integral equations for source functions of Ca II H, K and IR triplet lines for transfer through homogeneous stellar atmosphere
    Keywords: PHYSICS, ATOMIC, MOLECULAR, AND NUCLEAR
    Type: ; 95-142. (
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  • 5
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    Studies in spectral line formation. III - Non-linear multi-level atom problems. (1969)
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    Publication Date: 2019-06-27
    Description: Spectral line formation in nonlinear multilevel atom line transfer problems, considering radiation transfer through plane parallel atmospheres of H and Mg atoms
    Keywords: PHYSICS, ATOMIC, MOLECULAR, AND NUCLEAR
    Type: ; ADEMIE DES SCIENCES
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  • 6
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    Studies in spectral line formation. I, II. (1968)
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    Publication Date: 2019-06-27
    Description: Spectral lines source functions for formation in multilevel atom and radiative transfer in atmosphere of three level Na atoms and four level O atoms
    Keywords: PHYSICS, ATOMIC, MOLECULAR, AND NUCLEAR
    Type: ; ADEMIE DES SCIENCES
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  • 7
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    Frequency redistribution on scattering. (1967)
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    Publication Date: 2019-06-27
    Description: Frequency redistribution function of noncoherently scattered radiation, noting effect on source functions of two-level atoms
    Keywords: PHYSICS, ATOMIC, MOLECULAR, AND NUCLEAR
    Type: ASTROPHYSICAL JOURNAL
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  • 8
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    Theoretical intensity ratios for some Fe XIII coronal lines. (1973)
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    Publication Date: 2019-06-27
    Description: Using cross section values for collisional excitation by protons recently calculated by Landman (1973), theoretical values for the relative intensities of the Fe XIII 10747-, 10798-, and 3388-A lines are determined as functions of electron density. The obtained results are compared with those of Chevalier and Lambert (1969).
    Keywords: SPACE SCIENCES
    Type: Solar Physics; 30; June 197
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  • 9
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    Observed and theoretical profiles of the Si II lines at lambda 1814 (1978)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Emission line spectra observed at the limb of the solar disc are presented for transitions of singly ionized silicon at lambdas 1816.93, 1817.45 and 1808.01. The profiles show self-reversals in the line cores. A non-LTE analysis for a simplified model of the silicon ion is presented, and calculated line profiles are compared with the observations. The study indicates that some modification of the Vernazza et al. (1973) model of the solar chromosphere in the transition region is needed to reconcile the calculated and observed profiles.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 56; Feb. 197
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