Photospheric structure of an extended penumbra

Bellot Rubio, L. R. and Collados, M. and Ruiz Cobo, B. and Rodriguez Hidalgo, I. (2002) Photospheric structure of an extended penumbra. Il nuovo cimento C, 25 (5\6). pp. 543-549. ISSN 1826-9885

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The photospheric structure of an extended penumbra belonging to a complex spot observed near disk center is investigated by means of the inversion of the full Stokes vector of two Fe I lines at 1.56 μm. An attempt is made to classify the observed Stokes V profiles in terms of their shapes. It turns out that about 28% of the profiles have abnormal shapes indicative of two different magnetic-field components within the resolution element. The spatial distribution of abnormal Stokes V profiles is studied. It is found that such profiles are evenly distributed in the penumbra, without any particular tendency to concentrate near the so-called neutral line. Anomalous profiles are not only seen in the outer penumbra and beyond, but also in the middle part of it. A Milne-Eddington–like inversion is carried out first, revealing a smooth picture of the spatial distribution of magneticfield vector and velocities along the line of sight. In particular, dark spines with stronger and more vertical magnetic fields are seen to coexist with nearly horizontal magnetic fields throughout the penumbra. A full inversion allowing for gradients of the atmospheric parameters along the line of sight indicates the existence of cool magnetic tubes returning back to the solar surface (inclination angles greater than 90◦) and carrying the largest material flows.

Item Type: Article
Additional Information: Paper presented at the International Meeting on THEMIS and the New Frontiers of Solar Atmosphere Dynamics, Rome, Italy, March 19-21, 2001.
Uncontrolled Keywords: Photosphere, granulation ; Conference proceedings
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 12 Mar 2020 14:24
Last Modified: 12 Mar 2020 14:24

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