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A&A 442, 1079-1086 (2005)
DOI: 10.1051/0004-6361:20053257
The structure of a penumbral connection between solar pores
J. Hirzberger1, 2, S. Stangl1, K. Gersin1, J. Jurcák3, K. G. Puschmann4 and M. Sobotka31 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