uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Heating of the Magnetic Chromosphere: Observational Constraints from Ca II lambda 8542 Spectra
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
2013 (English)In: The Astrophysical Journal Letters, ISSN 2041-8205, Vol. 764, no 1, L11- p.Article in journal (Refereed) Published
Abstract [en]

The heating of the Sun's chromosphere remains poorly understood. While progress has been made on understanding what drives the quiet-Sun internetwork chromosphere, chromospheric heating in strong magnetic field regions continues to present a difficult challenge, mostly because of a lack of observational constraints. We use high-resolution spectropolarimetric data from the Swedish 1 m Solar Telescope to identify the location and spatio-temporal properties of heating in the magnetic chromosphere. In particular, we report the existence of raised-core spectral line profiles in the Ca II lambda 8542 line. These profiles are characterized by the absence of an absorption line core, showing a quasi-flat profile between. lambda approximate to +/- 0.5 angstrom, and are abundant close to magnetic bright points and plage. Comparison with three-dimensional MHD simulations indicates that such profiles occur when the line of sight goes through an "elevated temperature canopy" associated with the expansion with height of the magnetic field of flux concentrations. This temperature canopy in the simulations is caused by ohmic dissipation where there are strong magnetic field gradients. The raised-core profiles are thus indicators of locations of increased chromospheric heating. We characterize the location and temporal and spatial properties of such profiles in our observations, thus providing much stricter constraints on theoretical models of chromospheric heating mechanisms than before.

Place, publisher, year, edition, pages
2013. Vol. 764, no 1, L11- p.
Keyword [en]
line: formation, magnetohydrodynamics (MHD), polarization, Sun: chromosphere, Sun: faculae, plages, Sun: magnetic topology
National Category
Natural Sciences
URN: urn:nbn:se:uu:diva-196004DOI: 10.1088/2041-8205/764/1/L11ISI: 000314346700011OAI: oai:DiVA.org:uu-196004DiVA: diva2:609146
Available from: 2013-03-04 Created: 2013-03-04 Last updated: 2013-03-04Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
de la Cruz Rodriguez, Jaime
By organisation
Theoretical Astrophysics
Natural Sciences

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: 461 hits
ReferencesLink to record
Permanent link

Direct link