Magnetic structures of an emerging flux region in the solar photosphere and chromosphere

Xu, Z., A. Lagg, and S. K. Solanki, Magnetic structures of an emerging flux region in the solar photosphere and chromosphere, A&A, 520, A77 (2010) (ADS)

The cartoon

(click on the image for a larger version)

How one might envision "emerging flux," a cornerstone bit of jargon that describes what the Zeeman effect gives us in the observations of the surface of the Sun, but which does not help much to describe a very complicated 3D development. Here the lower plane is the photosphere, where we know as much as we can know about what is happening, subject to the resolution of our observations. The upper plane, described very loosely as the "upper chromosphere", is of course not a plane at all because of the structure imposed by the very magnetic field that the cartoon depicts. The green area shows a flux tube rising further up, poking into the corona, as the footpoints move apart (yellow arrows at the photosphere). The result is an Arch Filament System (AFS) This whole affair is fundamental, because it describes how violent coronal magnetic activity such as a flare may get its oomph.

Date: 2020 April 20