Volume 550, February 2013
|Number of page(s)||10|
|Published online||01 February 2013|
The velocity field of sunspot penumbrae
II. Return flow and magnetic fields of opposite polarity
Kiepenheuer Institut für Sonnenphysik, Schöneckstraße 6, 79104 Freiburg, Germany
e-mail: firstname.lastname@example.org; email@example.com
Received: 8 November 2012
Accepted: 19 December 2012
Aims. We search for penumbral magnetic fields of opposite polarity and for their correspondence with downflows.
Methods. We used spectropolarimetric HINODE data of a spot very close to disk center to suppress the horizontal velocity components as much as possible. We focus our study on 3-lobe Stokes V profiles.
Results. From forward modeling and inversions, we show that 3-lobe profiles testify to the presence of opposite magnetic fields. They occur predominately in the mid and outer penumbra and are associated with downflows in the deep layers of the photosphere.
Conclusions. Standard magnetograms show that only 4% of the penumbral area harbors magnetic fields of opposite polarity. If 3-lobe profiles are included in the analysis, this number increases to 17%.
Key words: sunspots / Sun: photosphere / Sun: magnetic topology / Sun: surface magnetism
© ESO, 2013
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