Document 
A&A 450, 383-393 (2006)
DOI: 10.1051/0004-6361:20054378
On the fine structure of sunspot penumbrae
III. The vertical extension of penumbral filaments
J. M. Borrero1, 2, S. K. Solanki1, A. Lagg1, H. Socas-Navarro2 and B. Lites21 Max-Planck Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
e-mail: borrero@ucar.edu
2 High Altitude Observatory, 3450 Mitchell Lane, Boulder, 80301 Colorado USA
(Received 19 October 2005 / Accepted 4 January 2006)
Abstract
In this paper we study the fine structure of the penumbra as inferred
from the uncombed model (flux tube embedded in a magnetic surrounding) when applied
to penumbral spectropolarimetric data from
the neutral iron lines at 6300 Å. The inversion infers very
similar radial dependences in the physical quantities (LOS velocity, magnetic
field strength etc.) as those obtained from the inversion of the Fe I
1.56 
m lines. In addition, the large Stokes V area
asymmetry exhibited by the visible lines helps to constrain the size of the
penumbral flux tubes. As we demonstrate here, the
uncombed model is able to reproduce the area asymmetry with striking
accuracy, returning flux tubes as thick as 100-300 kilometers in the vertical
direction, in good agreement with previous investigations.
Key words: Sun: sunspots -- Sun: magnetic fields
© ESO 2006