No abstract available

[en] Several atmospheric models for the sun are reviewed with the explanations of phenomena that can and cannot be derived from them. The various types of emission and spectral line shifts are discussed

[en] The Glossary is designed to be a technical dictionary that will provide solar workers of various specialities, students, other astronomers and theoreticians with concise information on the nature and properties of phenomena of solar and solar-terrestrial physics. Each term, or group of related terms, is given a concise phenomenological and quantitative description including the relationship to other phenomena and an interpretation in terms of physical processes. The references are intended to lead the non-specialist reader into the literature. This section deals with: quiet sun; atmospheric models; oscillations; short period oscillations; limb redshift; granulation ; photospheric network; chromospheric network; supergranulation; mottle; rosette and chain; chromospheric grain; spicule; interspicular region; macrospicule; chromospheric bubbles or 'bulles'; emission shell; flash spectrum; spectroheliograph; and birefringent filter. (B.R.H.)

No abstract available

[en] We searched for a variation with heliographic latitude of the solar limb effect by comparing the relative wavelengths of weak and strong Fraunhofer lines. The blue shifts associated with the limb effect appear 9% +- 5% larger in the polar radius vector than in an equatorial radius vector at cos THETA = 0.5. This should perhaps be interpreted as an increase with latitude of either solar convection or of convective overshoot. Recent observations of poleward meridional flows of 30 m s^-1 should be corrected for this limb effect variation. This correction increases this flow velocity to approx. 70 m s^-1. A search for a similar variation in plages and in network boundaries had negative results, the variation being +1% +- 5% and -1% +- 6% respectively. (orig.)

[en] Under the assumption that the horizontal velocities observed in the sunspot photosphere are caused by Alfven waves, the flux of these waves in the photosphere is found to be equal to 20--50 percent of the missing sunspot flux or 2--3 times the spot's flux of electromagnetic radiation. Since the downward-moving Alfven wave flux is likely to be similar to the upward-moving flux, this observation is consistent with the hypothesis that spots are cooled by their strong emission of Alfven waves

No abstract available

[en] The well-known correlation between granulation intensity and velocity fluctuations causes a shift of the average line position called the 'convective blue shift'. It is argued that this convective blue shift is most likely responsible for the limb effect of solar Fraunhofer lines. To explain the center-to-limb variation of this limb effect it is essential that both horizontal and vertical motions in the granulation are considered. The effects of a variation in the granulation properties across the Sun on large scale velocity pattern observations are discussed. Abnormal granulation patterns observed inactive regions and at the boundaries of supergranules could be responsible for part or all of the 'downflow' observed there. (Auth.)

[en] It has been suggested that pressure shifts are the sole cause for the systematic blue shift of solar Fraunhofer lines (Hart, 1974). To check this the significance of pressure shifts for Fe I lines is evaluated. The observed wavelength shifts of a large number of lines are compared with the shifts calculated for the Lennard-Jones potential following Hindmarsh et al. (1967). The Lennard-Jones poetential for the interatomic forces yield pressure shifts caused by neutral hydrogen, which explain only a small fraction of the observed blue shift. It is also shown that the quadratic Stark effect contributes insignificantly to the position of Fe I lines. (Auth.)

No abstract available