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The solar surface magnetic field is connected with and even controls most of the solar activity phenomena. Zeeman effect diagnostics allow for measuring only a small fraction of the fractal-like structured magnetic field. The remaining…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. I. Shapiro , D. M. Fluri , S. V. Berdyugina , M. Bianda , R. Ramelli

Given that dynamically significant magnetic fields in at least some massive stars have now been measured, our contribution addresses the question, to what extent can fields be directly detected in circumstellar gas? The question speaks…

Astrophysics · Physics 2007-08-20 Richard Ignace , Kenneth G. Gayley

The only way to obtain reliable empirical information on the intensity and topology of the weak magnetic fields of the quiet solar chromosphere is via the measurement and rigorous physical interpretation of polarization signals in…

Astrophysics · Physics 2011-04-12 J. Trujillo Bueno , R. Manso Sainz

This paper reviews some recent advances in the development and application of polarized radiation diagnostics to infer the mean magnetization of the quiet solar atmosphere, from the near equilibrium photosphere to the highly non-equilibrium…

Solar and Stellar Astrophysics · Physics 2010-02-15 J. Trujillo Bueno

Planets can emit polarized thermal radiation, just like brown dwarfs. We present calculated thermal polarization signals from hot exoplanets, using an advanced radiative transfer code that fully includes all orders of scattering by gaseous…

Earth and Planetary Astrophysics · Physics 2015-05-30 R. J. de Kok , D. M. Stam , T. Karalidi

The chromosphere of the quiet Sun is an important stellar atmospheric region whose thermal and magnetic structure we need to decipher for unlocking new discoveries in solar and stellar physics. To this end, we must identify and exploit…

Solar and Stellar Astrophysics · Physics 2015-05-19 R. Manso Sainz , J. Trujillo Bueno

Most of the quantitative information about the magnetic field vector in solar prominences comes from the analysis of the Hanle effect acting on lines formed by scattering. As these lines can be of non-negligible optical thickness, it is of…

Solar and Stellar Astrophysics · Physics 2016-12-21 Ivan Milic , Marianne Faurobert , Olga Atanackovic

The polarization of the Mg II h and k lines holds significant diagnostic potential for measuring chromospheric magnetic fields, which are crucial for understanding the physical processes governing the energy transport and dissipation in the…

Solar and Stellar Astrophysics · Physics 2026-01-01 Hao Li , Tanausú del Pino Alemán , Javier Trujillo Bueno

The polarization of radiation by scattering on an atom embedded in combined external quadrupole electric and uniform magnetic fields is studied theoretically. Analytic formulae are derived for the scattering phase matrix. Limiting cases of…

Astrophysics · Physics 2007-05-23 Yee Yee Oo , K. N. Nagendra , Sharath Ananthamurthy , G. Ramachandran

We employ the magnetic and velocity fields from turbulent dynamo simulations to synthesize the polarization of a typical photospheric line. The synthetic Stokes profiles have properties in common with those observed in the quiet Sun. The…

Astrophysics · Physics 2009-11-07 J. Sánchez Almeida , T. Emonet , F. Cattaneo

We consider the polarization arising from scattering in an envelope illuminated by a central anisotropic source. Spherical harmonics are used to describe both the light source anisotropy and the envelope density distribution functions of…

Astrophysics · Physics 2008-12-16 R Ignace , M Al-Malki , J Simmons , J C Brown , D Clarke , J Carson

The complex spectropolarimetric patterns around strong chromospheric lines, the result of subtle spectroscopic and transport mechanisms, are sensitive, sometimes in unexpected ways, to the presence of magnetic fields in the chromosphere,…

Solar and Stellar Astrophysics · Physics 2017-10-12 R. Manso Sainz , T. del Pino Alemán , R. Casini

We present the design and the prototype of the Small Synoptic Second Solar Spectrum Telescope (S5T), which can autonomously measure scattering polarization signals on a daily basis with large sensitivity and accuracy. Its data will be used…

Instrumentation and Methods for Astrophysics · Physics 2009-03-17 Frans Snik , Radek Melich , Christoph Keller

The Ly-alpha line of He II at 304 \AA\ is one of the spectral lines of choice for EUV channels of narrow-band imagers on board space telescopes, which provide spectacular intensity images of the outer solar atmosphere. Since the magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-03 Javier Trujillo Bueno , Jiri Stepan , Luca Belluzzi

This paper aims to study the polarization of hard X-ray (HXR) sources in the solar atmosphere, including Compton backscattering of photons in the photosphere (the albedo effect) and the spatial distribution of polarization across the…

Solar and Stellar Astrophysics · Physics 2015-05-30 Natasha Jeffrey , Eduard Kontar

The theory of the generation and transfer of polarized radiation, mainly developed for interpreting solar spectropolarimetric observations, allows to reconsider, in a more rigorous and elegant way, a physical mechanism that has been…

Astrophysics · Physics 2009-11-10 A. Asensio Ramos , E. Landi Degl'Innocenti , J. Trujillo Bueno

This paper considers the problem of modeling the light polarization that emerges from an astrophysical plasma composed of atoms whose excitation state is significantly influenced by the anisotropy of the incident radiation field. In…

Solar and Stellar Astrophysics · Physics 2011-05-03 Javier Trujillo Bueno

An innovative 3-D radar imaging technique is developed for fast and efficient identification and characterization of radar backscattering components of complex objects, when the collected scattered field is made of polarization-diverse…

Information Theory · Computer Science 2015-06-25 Pierre Minvielle , Pierre Massaloux , Jean-François Giovannelli

While there have been multiple observational programs aimed at detecting linear polarization of optical radiation emitted by ultracool dwarfs, there has been comparatively less rigorous theoretical analysis of the problem. The general…

Solar and Stellar Astrophysics · Physics 2014-11-20 Sujan Sengupta , Mark S. Marley

This is a theoretical investigation on the formation of the linearly polarized line spectrum of ionized cerium in the sun. We calculate the scattering line polarization pattern emergent from a plane-parallel layer of Ce {\sc ii} atoms…

Astrophysics · Physics 2009-11-11 R. Manso Sainz , E. Landi Degl'Innocenti , J. Trujillo Bueno