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Observations of the solar magnetic field are largely confined to the radiation emitted from the photosphere, the thin layer of the solar atmosphere which we call "the solar surface". It is from solar surface observations that we must infer the internal structure and the internal magnetohydrodynamic processes that lead to the multitude of fascinat ing phenomena of solar magnetic activity, and from solar surface observations we must also infer the interplay of convection and magnetism that regulates field dispersal, drives the heating of the outer-atmospheric plasma, and generates the solar wind. There is much to be learned from solar surface magnetism in physics and astrophysics; currently, there are rapid developments in this exciting field. The workshop of which this volume contains the proceedings aimed at a synthesis between observers and theorists, both with regard to the discrete elements that are the building blocks of solar magnetism and with regard to the larger-scale spatial and temporal patterns in which the magnetic elements emerge and disappear. The workshop was held during November 1-5, 1993 in Soesterberg, The Netherlands. The fifty participants took a very active part in making the workshop quite a lively one. The articles in these proceedings cover most of the oral and poster presentations, excepting a dozen soon to be published elsewhere.
Sommario
I. Context.- The Sun among the stars.- II. Techniques.- Recipes for solar polarimetry.- Some aspects of polarimetry with LEST.- Speckle techniques for spectroscopic observations.- The Fe I 10265 Å line as an excellent tool for magnetic field measurements.- III. Magnetic elements.- Properties of small magnetic elements.- Dynamics of small magnetic elements in a growing active region.- The upper photosphere and lower chromosphere of small-scale magnetic features.- Vector spectropolarimetry with the Advanced Stokes Polarimeter (ASP) for quantitative solar magnetometry.- Preliminary properties of pores derived from 1.56 micron lines.- The magnetic chromosphere.- Fine structures of the solar chromospheres.- Non-linearities of chromospheric oscillations.- Chromospheric oscillations.- Modelling umbrae.- Sunspot temperatures.- Interpretation of sunspot oscillations.- Dynamics of the Evershed effect.- The cause of the Evershed effect in sunspots: flows or waves?.- An analytical model for fluted sunspots and a new interpretation of Evershed flow.- Some consequences of an uncombed and inhomogeneous penumbra.- IV. Magnetic patterns.- On photospheric flows and chromospheric corks.- Large-scale photospheric motions: first results from an extraordinary eleven-hour granulation observation.- Solar magnetic fields and percolation theory.- Scaling properties of photospheric magnetic fields.- Magnetoconvective patterns.- Average east-west inclinations of surface magnetic field lines.- Magnetic field configurations basic to filament channels and filaments.- An observational and conceptual model of the magnetic field of a filament.- The solar magnetic cycle.- Cycle patterns of the axisymmetric magnetic field.- Returning to the random walk.- V. Theory of magnetoconvection.- The solardynamo.- Dynamics of erupting magnetic flux tubes.- Theory of passive magnetic field transport.- Dynamic interaction of convection with magnetic flux sheets: first results of a new MHD code.- Magnetoconvection and magnetoturbulence.- VI. Prospects.- Solar surface magnetism: quests for observations.- The THEMIS telescope.- THEMIS polarimetry.- SOHO: science objectives and capabilities.- Author index.- Citation index.
Relazione
`The volume is well produced and carefully edited by Rutten & Schrijver. It is most highly recommended as an excellent account of a key field ... '
Observatory, 115:1125
