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Detailed numerical models of chromosphere and corona are required to understand the heating of the solar atmosphere. An accurate treatment of the solar chromosphere is complicated by the effects arising from Non Local Thermodynamic…

Solar and Stellar Astrophysics · Physics 2022-08-17 D. Przybylski , R. Cameron , S. K. Solanki , M. Rempel , J. Leenaarts , L. S. Anusha , V. Witzke , A. I. Shapiro

The hydrogen Lyman lines ( 91.2 nm < lambda < 121.6 nm) are significant contributors to the radiative losses of the solar chromosphere, and are enhanced during flares. We have shown previously that the Lyman lines observed by the Extreme…

Solar and Stellar Astrophysics · Physics 2018-08-08 Stephen A Brown , Lyndsay Fletcher , Graham S Kerr , Nicolas Labrosse , Adam F Kowalski , Jaime De La Cruz Rodríguez

We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…

Solar and Stellar Astrophysics · Physics 2015-06-04 Jorrit Leenaarts , Mats Carlsson , Luc Rouppe van der Voort

In this paper we have extended our previous modeling of energy balance in the chromosphere-corona transition region to cases with particle and mass flows. The cases considered here are quasi-steady, and satisfy the momentum and energy…

Astrophysics · Physics 2009-11-07 J. M. Fontenla , E. H. Avrett , R. Loeser

Context. The radiative energy balance in the solar chromosphere is dominated by strong spectral lines that are formed out of LTE. It is computationally prohibitive to solve the full equations of radiative transfer and statistical…

Solar and Stellar Astrophysics · Physics 2015-06-04 Mats Carlsson , Jorrit Leenaarts

The Lyman Continuum (LyC; $<911.12$\AA) forms at the top of the chromosphere in the quiet-Sun, making LyC a powerful tool for probing the chromospheric plasma during solar flares. To understand the effects of non-thermal energy deposition…

Solar and Stellar Astrophysics · Physics 2023-03-01 Shaun A. McLaughlin , Ryan O. Milligan , Graham S. Kerr , Aaron J. Monson , Paulo J. A. Simões , Mihalis Mathioudakis

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 forward fitting of solar flare observations with radiation-hydrodynamic simulations is a common technique for learning about energy deposition and atmospheric evolution during these explosive events. A frequent spectral line choice for…

Solar and Stellar Astrophysics · Physics 2021-08-11 Christopher M. J. Osborne , Petr Heinzel , Jana Kašparová , Lyndsay Fletcher

Parameterizing radiative transfer in means navigating trade-offs between physical accuracy and conceptual clarity. However, currently available schemes sit at the extremes of this spectrum: correlated-k schemes are fast and accurate but…

Atmospheric and Oceanic Physics · Physics 2025-08-14 Andrew I. L. Williams

The ionization state of the gas in the dynamic solar chromosphere can depart strongly from the instantaneous statistical equilibrium commonly assumed in numerical modeling. We improve on earlier simulations of the solar atmosphere that only…

Solar and Stellar Astrophysics · Physics 2016-02-03 Thomas Peter Golding , Jorrit Leenaarts , Mats Carlsson

Spectral lines of helium are commonly observed on the Sun. These observations contain important informations about physical conditions and He/H abundance variations within solar outer structures. The modeling of chromospheric and coronal…

Solar and Stellar Astrophysics · Physics 2011-05-19 Pierre Gouttebroze , Nicolas Labrosse

The Lyman alpha (LyA) line of neutral hydrogen plays a central role in observations of star-forming galaxies. However, resonant scattering makes it difficult to directly interpret LyA signatures. Monte Carlo radiative transfer (MCRT)…

Astrophysics of Galaxies · Physics 2025-12-11 Kevin Lorinc , Aaron Smith , Olof Nebrin , Joshua Kasiri

Solar and thermal radiation are critical aspects of planetary climate, with gradients in radiative energy fluxes driving heating and cooling. Climate models require that radiative transfer tools be versatile, computationally efficient, and…

Earth and Planetary Astrophysics · Physics 2021-05-24 Tyler D. Robinson , David Crisp

The transition region is a thin layer of the solar atmosphere that controls the energy loss from the solar corona. Large numbers of grid points are required to resolve this thin transition region fully in numerical modeling. In this study,…

Solar and Stellar Astrophysics · Physics 2021-08-25 Haruhisa Iijima , Shinsuke Imada

Diagnostics for the solar chromosphere are relatively few compared to other parts of the atmosphere. Despite this, hundreds of Rydberg lines emitted by neutrals in this region have been observed at UV wavelengths. Here, we investigate their…

Solar and Stellar Astrophysics · Physics 2026-02-05 R. P. Dufresne , C. M. O. Osborne , G. Del Zanna

The solar radiation in the Lyman-alpha spectral line of hydrogen plays a significant role in the illumination of chromospheric and coronal structures, such as prominences, spicules, chromospheric fibrils, cores of coronal mass ejections,…

Solar and Stellar Astrophysics · Physics 2020-12-16 S. Gunar , P. Schwartz , J. Koza , P. Heinzel

Recent three-dimensional radiation hydrodynamic simulations by Wedemeyer et al. (2004) suggest that the solar chromosphere is highly structured in space and time on scales of only 1000 km and 20-25 sec, resp.. The resulting pattern consists…

Astrophysics · Physics 2007-05-23 S. Wedemeyer-Boehm , H. -G. Ludwig , M. Steffen , B. Freytag , H. Holweger

This document describes the publically available numerical code "IGMtransfer", capable of performing intergalactic radiative transfer (RT) of light in the vicinity of the Lyman alpha (Lya) line. Calculating the RT in a (possibly adaptively…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-17 Peter Laursen

Resonance lines encode rich information about astrophysical sources and their environments, yet fully analytic treatments of multi-line radiative transfer remain almost entirely unexplored. We present exact, closed-form solutions for…

Astrophysics of Galaxies · Physics 2026-02-18 Ethan Stace , Aaron Smith , Kevin Lorinc , Olof Nebrin

The Mg ii h&k lines are key diagnostics of the solar chromosphere. They are sensitive to the temperature, density, and non-thermal velocities in the chromosphere. The average Mg ii h&k line profiles arising from previous 3D chromospheric…

Solar and Stellar Astrophysics · Physics 2024-11-27 P. Ondratschek , D. Przybylski , H. N. Smitha , R. Cameron , S. K. Solanki , J. Leenaarts
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