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In addition to the `facular' brightening of active regions, the quiet Sun also contains a small scale magnetic field with associated brightenings in continuum radiation. We measure this contribution of quiet regions to the Sun's brightness…

Solar and Stellar Astrophysics · Physics 2011-08-11 R. S. Schnerr , H. C. Spruit

Parameters of magnetic flux distribution inside low-latitude coronal holes (CHs) were analyzed. A statistical study of 44 CHs based on Solar and Heliospheric Observatory (SOHO)/MDI full disk magnetograms and SOHO/EIT 284\AA images showed…

Solar and Stellar Astrophysics · Physics 2015-05-13 Valentina Abramenko , Vasyl Yurchyshyn , Hiroko Watanabe

Understanding many physical processes in the solar atmosphere requires determination of the magnetic field in each atmospheric layer. However, direct measurements of the magnetic field in the Sun's corona are difficult to obtain. Using…

Sunspots on the surface of the Sun are the observational signatures of intense manifestations of tightly packed magnetic field lines, with near-vertical field strengths exceeding 6,000 G in extreme cases. It is well accepted that both the…

A few years before the Hinode space telescope was launched, an investigation based on the Hanle effect in atomic and molecular lines indicated that the bulk of the quiet solar photosphere is significantly magnetized, due to the ubiquitous…

Solar and Stellar Astrophysics · Physics 2015-06-12 Nataliya Shchukina , Javier Trujillo Bueno

Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously…

Solar and Stellar Astrophysics · Physics 2020-11-05 Zihao Yang , Hui Tian , Steven Tomczyk , Richard Morton , Xianyong Bai , Tanmoy Samanta , Yajie Chen

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

Astrophysics · Physics 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer

As a large-scale motion on the Sun, the meridional flow plays an important role in determining magnetic structure and strength and solar cycle. However, the meridional flow near the solar poles is still unclear. The Hinode observations show…

Solar and Stellar Astrophysics · Physics 2024-07-29 Shuhong Yang , Jie Jiang , Zifan Wang , Yijun Hou , Chunlan Jin , Qiao Song , Yukun Luo , Ting Li , Jun Zhang , Yuzong Zhang , Guiping Zhou , Yuanyong Deng , Jingxiu Wang

We simulate the dynamics and the evolution of quiet Sun magnetic elements to produce a probability density function of the field strengths associated with such elements. The dynamics of the magnetic field are simulated through a numerical…

Astrophysics · Physics 2009-11-13 F. Berrilli , D. Del Moro , B. Viticchie

This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic…

Astrophysics · Physics 2009-11-13 R. K. Ulrich , L. Bertello , J. E. Boyden , L. Webster

We present a series of radiative MHD simulations addressing the origin and distribution of mixed polarity magnetic field in the solar photosphere. To this end we consider numerical simulations that cover the uppermost 2-6 Mm of the solar…

Solar and Stellar Astrophysics · Physics 2015-06-19 M. Rempel

Before using 3D MHD simulations of the solar photosphere in the determination of elemental abundances, one has to ensure that the correct amount of magnetic flux is present in the simulations. The presence of magnetic flux modifies the…

Solar and Stellar Astrophysics · Physics 2017-06-28 C. Beck , D. Fabbian , R. Rezaei , K. G. Puschmann

Electric currents in solar active regions are thought to provide the energy released via magnetic reconnection in solar flares. Vertical electric current densities $J_z$ at the photosphere may be estimated from vector magnetogram data,…

Solar and Stellar Astrophysics · Physics 2015-06-24 M. S. Wheatland

The Mg/Ne abundance ratio in the quiet Sun is measured in both network and supergranule cell centre regions through EUV spectra from the Coronal Diagnostic Spectrometer on SOHO. Twenty four sets of data over the period 1996 March to 1998…

Astrophysics · Physics 2009-11-10 P. R. Young

Three-dimensional magnetohydrodynamic simulations of the surface layers of the Sun intrinsically produce a predominantly horizontal magnetic field in the photosphere. This is a robust result in the sense that it arises from simulations with…

Solar and Stellar Astrophysics · Physics 2009-04-15 O. Steiner , R. Rezaei , R. Schlichenmaier , W. Schaffenberger , S. Wedemeyer-Böhm

The effect of a magnetic field on the spectral density of a $\rm{S=1/2}$ Kondo impurity is investigated at zero and finite temperatures by using Wilson's numerical renormalization group method. A splitting of the total spectral density is…

Strongly Correlated Electrons · Physics 2009-10-31 T. A. Costi

Using turbulent MHD simulations (magnetic Reynolds numbers up to 8000) and Hinode observations, we study effects of turbulence on measuring the solar magnetic field outside active regions. Firstly, from synthetic Stokes V profiles for the…

Astrophysics · Physics 2011-02-11 Jonathan Pietarila Graham , Sanja Danilovic , Manfred Schuessler

In the past, spectropolarimetric data from Hinode/SP has been employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors have found predominantly horizontal magnetic fields, others favor an…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. M. Borrero , P. Kobel

We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously-explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has…

Solar and Stellar Astrophysics · Physics 2015-06-19 Derek A. Lamb , Timothy A. Howard , Craig E. DeForest

We compare photospheric line-of-sight magnetograms from the Synoptic Long-term Investigations of the Sun (SOLIS) vector spectromagnetograph (VSM) instrument with observations from the 150-foot Solar Tower at Mt. Wilson (MWO), Helioseismic…

Solar and Stellar Astrophysics · Physics 2012-10-01 A. Pietarila , L. Bertello , J. W. Harvey , A. A. Pevtsov