Change search
ReferencesLink to record
Permanent link

Direct link
Magnetostatic penumbra models with field-free gaps
Stockholm University, Faculty of Science, Department of Astronomy. Institutet för solfysik.
2006 (English)In: Astronomy & Astrophysics, ISSN 0004-6361, Vol. 460, no 2, 605-615 p.Article in journal (Refereed) Published
Abstract [en]

We present numerical 2D magnetostatic models for sunspot penumbrae consisting of radially aligned field-free gaps in a potential magnetic field, as proposed by Spruit & Scharmer (2006, A&A, 447, 343). The shape of the gaps and the field configurations around them are computed consistently from the condition of magnetostatic pressure balance between the gap and the magnetic field. The results show that field-free gaps in the inner penumbra are cusp-shaped and bounded by a magnetic field inclined by about 70° from the vertical. Here, the magnetic component has a Wilson depression on the order 200-300 km relative to the top of the field-free gap; the gaps should thus appear as noticeably elevated features. This structure explains the large variations in field strength in the inner penumbra inferred from magnetograms and two-component inversions, and the varying appearance of the inner penumbra with viewing angle. In the outer penumbra, on the other hand, the gaps are flat-topped with a horizontal magnetic field above the middle of the gap. The magnetic field has large inclination variations horizontally, but only small fluctuations in field strength, in agreement with observations.

Place, publisher, year, edition, pages
2006. Vol. 460, no 2, 605-615 p.
Keyword [en]
sunspots, magnetic fields, magnetohydrodynamics (MHD), plasmas, Sun: magnetic fields
National Category
Astronomy, Astrophysics and Cosmology Fusion, Plasma and Space Physics
URN: urn:nbn:se:su:diva-20165DOI: doi:10.1051/0004-6361:20066019OAI: diva2:186690
Available from: 2007-02-27 Created: 2007-02-27 Last updated: 2011-01-11Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Scharmer, Göran
By organisation
Department of Astronomy
Astronomy, Astrophysics and CosmologyFusion, Plasma and Space Physics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 37 hits
ReferencesLink to record
Permanent link

Direct link