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Astron. Astrophys. 333, 305-312 (1998)

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Properties of solar pores

Peter Sütterlin

Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg, Germany

Received 20 November 1997 / Accepted 19 January 1998


We present the results of an extensive investigation of the properties of solar pores. Spectra of all 4 Stokes parameters of several magnetic sensitive absorption lines as well as Stokes [FORMULA] only spectra of lines with low or vanishing Landé-factor have been observed. An inversion code based on the Levenberg-Marquardt algorithm was written, incorporating the full radiative transfer equations. This code adapts a set of parameters that are used to represent the magnetic and thermodynamic state of the atmosphere to best-fit a set of observed line profiles.

The results show that the value of all relevant parameters are intimately related to the size of the pores, therewith confirming the role of solar pores as a link between (bright) magnetic flux tubes and sunspots. In particular the inclination of the magnetic field lines at the outer rim of a pore, which is affected by the vertical field gradient, seems to put an upper limit on the diameter of pores where the inclination reaches a value that might trigger the formation of a penumbra.

Key words: Sun: magnetic fields – sunspots – polarization

Present address: Universitäts-Sternwarte, Geismarlandstrasse 11, D-37083 Göttingen, Germany Correspondence to: pit@uni-sw.gwdg.de

Send offprint requests to: Correspondence to: pit@uni-sw.gwdg.de

© European Southern Observatory (ESO) 1998

Online publication: April 15, 1998