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The O I 1355{\AA} spectral line is one of the only optically thin lines that are both routinely observed and thought to be formed in the chromosphere. We present analysis of a variety of observations of this line with the Interface Region…

Solar and Stellar Astrophysics · Physics 2023-08-29 Mats Carlsson , Bart De Pontieu

For many years various asymmetrical profiles of different spectral lines emitted from solar flares have been frequently observed. These asymmetries or line shifts are caused predominantly by vertical mass motions in flaring layers and they…

Astrophysics · Physics 2007-05-23 A. Berlicki

We report on a detailed radiative transfer modeling of the observed scattering polarization in the H-alpha line, which allows us to infer quantitative information on the magnetization of the quiet solar chromosphere. Our analysis suggests…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jiri Stepan , Javier Trujillo Bueno

We investigate the fine structure of magnetic fields in the atmosphere of the quiet Sun. We use photospheric magnetic field measurements from {\sc Sunrise}/IMaX with unprecedented spatial resolution to extrapolate the photospheric magnetic…

The Hanle effect in strong spectral lines is the physical mechanism that should be increasingly exploited for quantitative explorations of the magnetism of the quiet solar chromospheric plasma. Here we show, by means of multilevel radiative…

Solar and Stellar Astrophysics · Physics 2011-02-25 Jiri Stepan , Javier Trujillo Bueno , Renzo Ramelli , Michele Bianda

On 12 March 1996 we obtained observations of the quiet Sun with the SUMER instrument. The observa- tions were sequences of 15-20 second exposures of ultraviolet emission line profiles and of the neighboring continua. These data contain…

Astrophysics · Physics 2009-10-30 Mats Carlsson , Philip G. Judge , Klaus Wilhelm

Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal…

Astrophysics · Physics 2007-05-23 J. Trujillo Bueno , N. Shchukina , A. Asensio Ramos

Understanding the dynamics of the solar chromosphere is crucial to understanding energy transport across the solar atmosphere. The chromosphere is optically thick at many wavelengths and described by non-local thermodynamic equilibrium…

Solar and Stellar Astrophysics · Physics 2019-01-30 Jeffrey W. Reep , Stephen J. Bradshaw , Nicholas A. Crump , Harry P. Warren

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 Ca II infrared triplet is one of the few magnetically sensitive chromospheric lines available for ground-based observations. We present spectropolarimetric observations of the 8498 A and 8542 A lines in a quiet Sun region near a…

Astrophysics · Physics 2009-11-13 A. Pietarila , H. Socas-Navarro , T. Bogdan

Context. A proper estimate of the chromospheric magnetic fields is believed to improve modelling of both active region and coronal mass ejection evolution. Aims. We investigate the similarity between the chromospheric magnetic field…

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

The physics of the solar chromosphere depends in a crucial way on its magnetic structure. However there are presently very few direct magnetic field diagnostics available for this region. Here we investigate the diagnostic potential of the…

Astrophysics · Physics 2009-11-13 M. Faurobert , M. Derouich , V. Bommier , J. Arnaud

Future solar missions and ground-based telescopes aim to understand the magnetism of the solar chromosphere. We performed a supporting study in Quintero Noda et al. (2016) focused on the infrared Ca II 8542 A line and we concluded that is…

Solar and Stellar Astrophysics · Physics 2016-12-07 C. Quintero Noda , T. Shimizu , Y. Katsukawa , J. de la Cruz Rodriguez , M. Carlsson , T. Anan , T. Oba , K. Ichimoto , Y. Suematsu

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

It has so far proven impossible to reproduce all aspects of the solar plage chromosphere in quasi-realistic numerical models. The magnetic field configuration in the lower atmosphere is one of the few free parameters in such simulations.…

Solar and Stellar Astrophysics · Physics 2021-01-04 A. G. M. Pietrow , D. Kiselman , J. de la Cruz Rodríguez , C. J. Díaz Baso , A. Pastor Yabar , R. Yadav

The nonlinear force-free field (NLFFF) modeling has been extensively used to infer the three-dimensional (3D) magnetic field in the solar corona. One of the assumptions in the NLFFF extrapolation is that the plasma beta is low, but this…

Solar and Stellar Astrophysics · Physics 2020-07-30 Yusuke Kawabata , Andrés Asensio Ramos , Satoshi Inoue , Toshifumi Shimizu

Spectral diagnostic features formed in the solar chromosphere are few and difficult to interpret -- they are neither formed in the optically thin regime nor in local thermodynamic equilibrium (LTE). To probe the state of the chromosphere,…

Astrophysics · Physics 2007-05-23 M. Carlsson

The solar chromosphere is very dynamic, due to the presence of large amplitude hydrodynamic waves. Their propagation is affected by NLTE radiative transport in strong spectral lines, which can in turn be used to diagnose the dynamics of the…

Astrophysics · Physics 2009-11-13 R. Hammer , P. Ulmschneider

We investigate the synthesis of the Balmer and Paschen lines of the quiet Sun, using both classical semi-empirical and theoretical model atmospheres, modern line broadening theory and non-LTE line-formation. The computations alleviate…

Astrophysics · Physics 2009-11-10 Norbert Przybilla , Keith Butler