Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-03-27
Astrophys.J.660:863-873,2007
Astronomy and Astrophysics
Astrophysics
17 pages, 5 figures. In press, ApJ - est. Vol. 660, No. 1, 2007 May 1
Scientific paper
10.1086/512671
The study of magnetic connectivity in the solar corona reveals a need to generalize the field line mapping technique to arbitrary geometry of the boundaries and systems of coordinates. Indeed, the global description of the connectivity in the corona requires the use of the photospheric and solar wind boundaries. Both are closed surfaces and therefore do not admit a global regular system of coordinates. At least two overlapping regular systems of coordinates for each of the boundaries are necessary in this case to avoid spherical-pole-like singularities in the coordinates of the footpoints. This implies that the basic characteristic of magnetic connectivity - the squashing degree or factor $Q$ of elemental flux tubes (Titov et al., 2002) - must be rewritten in covariant form. Such a covariant expression of $Q$ is derived in this work. The derived expression is very flexible and highly efficient for describing the global magnetic connectivity in the solar corona. In addition, a general expression for a new characteristic $Q_\perp$ which defines a squashing of the flux tubes in the directions perpendicular to the field lines is determined. This new quantity makes it possible to filter out the quasi-separatrix layers whose large values of $Q$ are caused by a projection effect at the field lines nearly touching the photosphere. Thus, the value $Q_\perp$ provides a much more precise description of the volumetric properties of the magnetic field structure. The difference between $Q$ and $Q_\perp$ is illustrated by comparing their distributions for two configurations, one of which is the Titov-Demoulin (1999) model of a twisted magnetic field.
No associations
LandOfFree
Generalized Squashing Factors for Covariant Description of Magnetic Connectivity in the Solar Corona does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Generalized Squashing Factors for Covariant Description of Magnetic Connectivity in the Solar Corona, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Generalized Squashing Factors for Covariant Description of Magnetic Connectivity in the Solar Corona will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-371910