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This paper is concerned with the Laplace boundary-value problem with the directional derivative, corresponding to the specific nature of measurements of the longitudinal component of the photospheric magnetic field. Boundary conditions are…

Astrophysics · Physics 2015-06-24 G. V. Rudenko

The problem of solar chromospheric heating remains a challenging one with wider implications for stellar physics. Several studies in the recent past have shown that small-scale inclined magnetic field elements channel copious amount of…

Solar and Stellar Astrophysics · Physics 2018-12-14 S. P. Rajaguru , C. R. Sangeetha , Durgesh Tripathi

The distribution of magnetic field strength at different levels in the solar photosphere outside active regions was obtained on the basis of the 2D MHD simulation of magnetogranulation and the synthesis of the V profiles of the Fe I 1564.8…

Solar and Stellar Astrophysics · Physics 2012-09-28 V. A. Sheminova

The presence of magnetic field is crucial in the transport of energy through the solar atmosphere. Recent ground-based and space-borne observations of the quiet Sun have revealed that magnetic field accumulates at photospheric heights, via…

Solar and Stellar Astrophysics · Physics 2019-06-19 Juan Martínez-Sykora , Viggo H. Hansteen , Boris Gudiksen , Mats Carlsson , Bart De Pontieu , Milan Gosic

It has long been known that magnetic plage and sunspots are regions in which the power of acoustic waves is reduced within the photospheric layers. Recent observations now suggest that this suppression of power extends into the low…

Solar and Stellar Astrophysics · Physics 2015-06-19 Rekha Jain , Andrew Gascoyne , Bradley W. Hindman , Benjamin Greer

The plasma-$\beta$ is an important fundamental physical quantity in solar plasma physics, which determines the dominating process in the solar atmosphere, i.e., magnetic or thermodynamic processes. Here, for the first time, we provide…

Solar and Stellar Astrophysics · Physics 2025-07-23 Ananya Rawat , Girjesh Gupta , Tom Van Doorsselaere , S. Krishna Prasad , Robertus Erdélyi

Magnetic elements have an intensity contrast that depends on the type of region they are located in (e.g. quiet Sun, or active region plage). Observed values also depend on the spatial resolution of the data. Here we investigate the…

Solar and Stellar Astrophysics · Physics 2019-01-16 F. Kahil , T. L. Riethmüller , S. K. Solanki

In this paper, a new sampling scheme of the near field radiated by a planar source is proposed and assessed. More in detail, the paper shows a uniform sampling criterion that allows representing the near field over a plane with a number of…

Signal Processing · Electrical Eng. & Systems 2024-02-13 Raffaele Moretta , Fabio Pascariello , Giovanni Petraglia , Maurizio Feo , Maria Antonia Maisto

The Mg II h and k lines are among the strongest in the near-ultraviolet solar spectrum and their line core originates in the upper chromosphere, just below the transition region. Consequently, they have become one of the main targets for…

Solar and Stellar Astrophysics · Physics 2023-01-18 David Afonso Delgado , Tanausú del Pino Alemán , Javier Trujillo Bueno

Magnetic fields are ubiquitous in the Universe. Recently, cosmological simulations of galaxies have successfully begun to incorporate magnetic fields and their evolution in galaxies and their haloes. However, so far they have mostly focused…

We report the discovery of a new magnetic DA white dwarf (WD), WD0011-721, which is located within the very important 20pc volume-limited sample of the closest WDs to the Sun. This star has a mean field modulus <|B|> of 343 kG, and from the…

Solar and Stellar Astrophysics · Physics 2019-08-07 John D. Landstreet , Stefano Bagnulo

The Zeeman effect is of limited utility for probing the magnetism of the quiet solar chromosphere. The Hanle effect in some spectral lines is sensitive to such magnetism, but the interpretation of the scattering polarization signals…

Solar and Stellar Astrophysics · Physics 2021-04-21 Jan Jurcak , Jiri Stepan , Javier Trujillo Bueno

The magnetic field of a sunspot guides magnetohydrodynamic waves toward higher atmospheric layers. In the upper photosphere and lower chromosphere, wave modes with periods longer than the acoustic cut-off period become evanescent. The…

Solar and Stellar Astrophysics · Physics 2016-12-07 J. Löhner-Böttcher , N. Bello González , W. Schmidt

The magnetic field inside the sunspot umbra, as observed by the Full-disk MagnetoGraph (FMG) onboard the Advanced Space based Solar Observatory (ASO-S), was found to be experiencing a weakening. To address this issue, we employed a method…

Solar and Stellar Astrophysics · Physics 2024-05-30 Haiqing Xu , Jiangtao Su , Suo Liu , Yuanyong Deng , Xianyong Bai , Jie Chen , Xiaofan Wang , Xiao Yang , Yongliang Song

Context. Magnetic fields are key to understand galaxy evolution, regulating stellar feedback and star formation in galaxies. Aims. We probe the origin of magnetic fields in late-type galaxies, measuring magnetic field strengths, exploring…

We use state-of-the-art, three-dimensional non-local thermodynamic equilibrium (non-LTE) radiative magnetohydrodynamic simulations of the quiet solar atmosphere to carry out detailed tests of chromospheric magnetic field diagnostics from…

Solar and Stellar Astrophysics · Physics 2017-04-26 Maria Loukitcheva , Stephen M. White , Sami K. Solanki , Gregory D. Fleishman , Mats Carlsson

Electron density irregularities in the ionosphere are known to be magnetically anisotropic, preferentially elongated along the lines of force. While many studies of their morphology have been undertaken by topside sounding and whistler…

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

Dissipation of magnetohydrodynamic (MHD) wave energy has been proposed as a viable heating mechanism in the solar chromospheric plasma. Here, we use a simplified one-dimensional model of the chromosphere to theoretically investigate the…

Solar and Stellar Astrophysics · Physics 2015-09-23 Roberto Soler , Marc Carbonell , Jose Luis Ballester

We investigate the magnetic field of a sunspot in the upper chromosphere and compare it to the field's photospheric properties. We observed the main leading sunspot of the active region NOAA 11124 on two days with the Tenrife Infrared…

Solar and Stellar Astrophysics · Physics 2017-08-23 Jayant Joshi , Andreas Lagg , Johann Hirzberger , Sami K. Solanki