EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 369/2 Article
Free access article

Issue A&A
Volume 369, Number 2, April II 2001
Page(s) 646 - 659
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20010120



A&A 369, 646-659 (2001)
DOI: 10.1051/0004-6361:20010120

Empirical models of solar magnetic flux-tubes and their non-magnetic surroundings

C. Frutiger1 and S. K. Solanki2

1  Institute of Astronomy, ETH-Zentrum, 8092 Zürich, Switzerland
2  Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany

(Received 21 July 2000 / Accepted 12 January 2001 )

Abstract
A powerful method for the analysis of the structure of small scale magnetic elements in the solar photosphere is the inversion of Stokes spectra. In previous papers based on such inversions Bellot Rubio et al. (1997, 1999) and Frutiger et al. (1999) have argued in favor of models with rather different dynamic properties. In this paper we return to this debate and compare results returned by inversions based on new multi-component models applied to several Fe I, Fe II and C I spectral line profiles obtained in active region plage with a Fourier Transform Spectrometer. These inversions differ from earlier ones by the fact that mass conservation is strictly imposed both inside the magnetic elements and on the surrounding external flow field. These flux-tube models are not only able to reproduce the characteristic Stokes V asymmetries and line-shifts observed in active regions plages or network elements, but also the Stokes I line profiles, including line bisectors. It is confirmed that from the quality of the fits alone it is not possible to distinguish between the steady flow proposed by Bellot Rubio et al. (1997) and the oscillatory model of Frutiger & Solanki (1998). If, however, physical constraints are imposed (e.g. mass conservation or that the flow retains the same direction over height in the flux tube) then the oscillatory model is found to be superior. In addition, the current investigation also provides the first inversion-based model of abnormal granulation.


Key words: polarization -- radiative transfer -- Sun: faculae, plages -- Sun: granulation -- Sun: magnetic fields

Offprint request: C. Frutiger, frutiger@astro.phys.ethz.ch




© ESO 2001


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.