A&A 442, 1079-1086 (2005)
DOI: 10.1051/0004-6361:20053257

The structure of a penumbral connection between solar pores

J. Hirzberger^{1, 2}, S. Stangl¹, K. Gersin¹, J. Jurcák³, K. G. Puschmann⁴ and M. Sobotka<sup>3

1</sup>  Institut für Physik, IGAM, Universitätsplatz 5, 8010 Graz, Austria
²  Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
    e-mail: hirzberger@mps.mpg.de
³  Astronomical Institute, Academy of Sciences of the Czech Republic, 25165 Ondrejov, Czech Republic
⁴  Universitäts-Sternwarte, Geismarlandstraße 11, 37083 Göttingen, Germany

(Received 18 April 2005 / Accepted 17 June 2005 )

Abstract
High resolution 2D-spectro-polarimetric observations have been used to analyse the magnetic field and flow topologies of a penumbral connection between two opposite polarity solar pores. A filamentary structured Evershed-like material flow from one pore to the other along the magnetic field lines has been detected. The flow channels are co-spatial with bright penumbral filaments close to the pore which feeds the flow and the clear brightness-velocity relation vanishes close to the pore which represents the sink of the flow. The boundary between umbra and penumbra of the two pores show significant differences: bright comet-like penumbral grains represent endings of penumbral filaments at the flow sources whereas no such grains were found at the sinks of the flow. Furthermore, a systematic variation of the asymmetries of measured Stokes V profiles across the penumbral connection have been found. The obtained results are in accordance with the widely-accepted uncombed penumbra hypothesis and the moving flux tube model.

Key words: Sun: photosphere -- Sun: magnetic fields -- Sun: sunspots

© ESO 2005

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