2005/09/09 by I. Domínguez Cerdeña, I. Dominguez Cerdena, J. Sánchez Alméida +2
Mathematics · Physics and Astronomy · #Astronomy #Astrophysics #Computational physics #Coronal mass ejection #Field (mathematics) #Field strength #Flux (metallurgy) #Ionosphere and magnetosphere dynamics #Magnetic energy #Magnetic field #Magnetic flux #Magnetization #Materials science #Mathematics #Photosphere #Physics #QUIET #Quantum mechanics #Solar and Space Plasma Dynamics #Solar wind #Stellar magnetic field #Stellar, planetary, and galactic studies #Zeeman effect #astro-ph
paper · pdf · doi:10.1086/497955
published as Astrophys.J.636:496-509,2005 · To appear in ApJ. 14 pages, 9 figures
arxiv created 2005/09/09 · openalex publication_date 2005/12/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The quiet-Sun photospheric plasma has a variety of magnetic field strengths going from zero to 1800 G. The empirical characterization of these field strengths requires a probability density function (PDF), i.e., a function P ( B ) describing the fraction of quiet Sun occupied by each field strength B . We show how to combine magnetic field strength measurements based on the Zeeman effect and the Hanle effect to estimate an unbiased P ( B ). The application of the method to real observations renders a set of possible PDFs, which outline the general characteristics of the quiet-Sun magnetic fields. Their most probable field strength differs from zero. The magnetic energy density is a significant fraction of the kinetic energy of the granular motions at the base of the photosphere (larger than 15% or larger than 2 × 10 3 ergs cm -3 ). The unsigned flux density (or mean magnetic field strength) has to be between 130 and 190 G. A significant part of the unsigned flux (between 10% and 50%) and of the magnetic energy (between 45% and 85%) are provided by the field strengths larger than 500 G, which, however, occupy only a small fraction of the surface (between 1% and 10%). The fraction of kG fields in the quiet Sun is even smaller, but they are important for a number of reasons. The kG fields still trace a significant fraction of the total magnetic energy, they reach the high photosphere, and they appear in unpolarized light images. The quiet-Sun photosphere has far more unsigned magnetic flux and magnetic energy than the active regions and the network combined.