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Related papers: Full non-LTE spectral line formation I. Setting th…

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The astrophysically very interesting Li I 671 nm line has been observed with high spatial resolution in solar granulation with the intention to diagnose departures from local thermodynamic equilibrium (LTE) in the line formation. The…

Astrophysics · Physics 2007-05-23 Dan Kiselman

The efficient numerical solution of Non-LTE multilevel transfer problems requires the combination of highly convergent iterative schemes with fast and accurate formal solution methods of the radiative transfer (RT) equation. This…

Astrophysics · Physics 2007-10-30 P. Fabiani Bendicho , J. Trujillo Bueno

Non-LTE calculations are performed for NII in stellar atmospheric models appropriate to main sequence B-stars to produce new grids of equivalent widths for the strongest NII lines commonly used for abundance analysis. There is reasonable…

Solar and Stellar Astrophysics · Physics 2015-11-18 A. Ahmed , T. A. A. Sigut

We consider a relativistic radiating spherical star in conformally flat spacetimes. In particular we study the junction condition relating the radial pressure to the heat flux at the boundary of the star which is a nonlinear partial…

General Relativity and Quantum Cosmology · Physics 2014-12-23 G. Abebe , K. S. Govinder , S. D. Maharaj

Context. B-type supergiants are versatile tools to address various astrophysical topics, ranging from stellar atmospheres over stellar and galactic evolution to the cosmic distance scale. Aims. A hybrid non-LTE approach - line-blanketed…

Solar and Stellar Astrophysics · Physics 2023-01-10 D. Weßmayer , N. Przybilla , K. Butler

One of the challenges of the modern photonics is to develop all-optical devices enabling increased speed and energy efficiency for transmitting and processing information on an optical chip. It is believed that the recently suggested…

An improved formulation of the one-step model of photoemission from crystal surfaces is proposed which overcomes different limitations of the original theory. Considering the results of an electronic-structure calculation, the electronic…

Strongly Correlated Electrons · Physics 2015-06-25 C. Meyer , M. Potthoff , W. Nolting , G. Borstel , J. Braun

The standard theory of electromagnetic cascades onto a photon background predicts a quasi-universal shape for the resulting non-thermal photon spectrum. This has been applied to very disparate fields, including non-thermal big bang…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-05 Vivian Poulin , Pasquale D. Serpico

The theory of a response of a two-energy-level system, irradiated by symmetrical light pulses, has been developed.(Suchlike electronic system approximates under the definite conditions a single ideal quantum well (QW) in a strong magnetic…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 L. I. Korovin , I. G. Lang D. A. Contreras-Solorio , S. T. Pavlov

We study the linear dynamics of spectrally stable $T$-periodic stationary solutions of the Lugiato-Lefever equation (LLE), a damped nonlinear Schr\"odinger equation with forcing that arises in nonlinear optics. Such $T$-periodic solutions…

Analysis of PDEs · Mathematics 2021-01-18 Mariana Haragus , Mathew A. Johnson , Wesley R. Perkins

Although the frequency shift and odd-even intensity modulation in high-order harmonic generation (HHG) have both been observed for asymmetric laser-target systems, they are typically studied as two separate phenomena. In this Letter, we…

Optics · Physics 2024-06-14 Doan-An Trieu , Van-Hoang Le , Ngoc-Loan Phan

Numerical transfer matrices have been widely used in the study of wave propagation and scattering. These may be viewed as descretizations of a recently introduced fundamental notion of transfer matrix which admits a representation in terms…

Classical Physics · Physics 2023-10-03 Farhang Loran , Ali Mostafazadeh

As one of the most important elements in astronomy, iron abundance determinations need to be as accurate as possible. We investigate the accuracy of spectroscopic iron abundance analyses using archetypal metal-poor stars. We perform…

Solar and Stellar Astrophysics · Physics 2016-09-15 A. M. Amarsi , K. Lind , M. Asplund , P. S. Barklem , R. Collet

In the first three papers of this series, we investigated the formation of photospheric neutral iron lines in different atmospheres ranging from idealised flux tube models to complex three-dimensional magnetohydrodynamic (3D MHD)…

Solar and Stellar Astrophysics · Physics 2025-05-14 R. Holzreuter , H. N. Smitha , S. K. Solanki

A class of models of heat transfer processes in a multilayer domain is considered. The governing equation is a nonlinear heat-transfer equation with different temperature-dependent densities and thermal coefficients in each layer.…

Numerical Analysis · Mathematics 2018-04-30 Milena Veneva , Alexander Ayriyan

The concept of spectrum for a class of non-linear wave equations is studied. Instead of looking for stability, the key to the spectral structure is found in the instability phenomena (bifurcations). This aspect is best seen in the…

Quantum Physics · Physics 2016-11-14 P. Grochowski , W. Kaniowski , B. Mielnik

Using 1D NLTE radiative hydrodynamics we model the influence of the particle beams on the Halpha line profile treating the beam propagation and the atmosphere evolution self-consistently. We focus on the influence of the non-thermal…

Astrophysics · Physics 2008-11-26 J. Kasparova , M. Varady , M. Karlicky , P. Heinzel , Z. Moravec

The paper describes the modelling of the structure and spectra of the hot accretion spots on the surface of young stars with taking into account departures from LTE for hydrogen and helium. It has been found that the existence of the ram…

Solar and Stellar Astrophysics · Physics 2015-07-01 A. V. Dodin

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars.…

Solar and Stellar Astrophysics · Physics 2017-11-28 Thomas Nordlander , Karin Lind

The nonlinear propagation of intense incoherent photons in a photon gas is considered. The photon-photon interactions are governed by a pair of equations comprising a wave-kinetic equation for the incoherent photons in the presence of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Padma K. Shukla , Mattias Marklund , Gert Brodin , Lennart Stenflo