Nonlinear transfer problem for general frequency redistribution laws

Astrophysics ◽  
1986 ◽  
Vol 23 (1) ◽  
pp. 458-468
Author(s):  
N. B. Engibaryan ◽  
A. Kh. Khachatryan
Keyword(s):  
Transfer Problem ◽  
Frequency Redistribution ◽  
Nonlinear Transfer ◽  
General Frequency

scholarly journals Hydrogen Line Profiles

1995 ◽  
Vol 10 ◽  
pp. 411-414 ◽  
Author(s):  
I. Hubeny
Keyword(s):  
Transfer Problem ◽  
Current Status ◽  
Line Profiles ◽  
Line Broadening ◽  
Hydrogen Line ◽  
Radiative Transfer Problem ◽  
Frequency Redistribution ◽  
Sufficient Detail ◽  
High Degree ◽  
Complete Frequency

Observed hydrogen line profiles are an enormously important source of diagnostic information about virtually all kinds of astronomical bodies. Therefore, it is important to understand the hydrogen line formation in sufficient detail to be able to achieve a high degree of reliability by analyzing observed hydrogen line profiles.Calculation of the predicted hydrogen line profiles involves two basic ingredients, (i) intrinsic line profiles, or line broadening - ”atomic physics” part, and (ii) the radiative transfer problem - ”astrophysics” part. There is not enough space to discuss here the current status of the astrophysical part of the problem. Fortunately, this topic is covered by many reviews. There are two major problems here, (a) departures from local thermodynamic equilibrium (LTE) - the so-called non-LTE description (e.g. Mihalas 1978; Hubenyet al.1994); and (b) departures from complete frequency redistribution (Cooperet al.1989; Hubeny and Lites 1994).

Effects of Ambipolar Diffusion on Prominence Thread Models

1994 ◽  
Vol 144 ◽  
pp. 315-321 ◽  
Author(s):  
M. G. Rovira ◽  
J. M. Fontenla ◽  
J.-C. Vial ◽  
P. Gouttebroze
Keyword(s):  
Energy Balance ◽  
Transition Region ◽  
Ambipolar Diffusion ◽  
Line Profiles ◽  
Balance Equations ◽  
Model Calculations ◽  
Partial Frequency ◽  
Frequency Redistribution ◽  
Partial Frequency Redistribution ◽  
Theoretical Structure

AbstractWe have improved previous model calculations of the prominence-corona transition region including the effect of the ambipolar diffusion in the statistical equilibrium and energy balance equations. We show its influence on the different parameters that characterize the resulting prominence theoretical structure. We take into account the effect of the partial frequency redistribution (PRD) in the line profiles and total intensities calculations.

Frequency Redistribution Effects in the Formation of Lyman α in Prominences and Their Influence on the Ratio of Hα to Lα

1979 ◽  
Vol 44 ◽  
pp. 53-55
Author(s):  
R.W. Milkey ◽  
J.N. Heasley ◽  
E.J. Schmahl ◽  
O. Engvold
Keyword(s):  
Line Profile ◽  
Large Fraction ◽  
Partial Frequency ◽  
Frequency Redistribution ◽  
Partial Frequency Redistribution ◽  
Emergent Intensity

The effect of partial frequency redistribution in the formation of Lyman α in the chromosphere has been discussed by Milkey and Mihalas (1973) and others, and it has been shown that in this case the coherency of scattering in the wings of the line substantially influences the line profile. Although there are non-negligible sources for La photons within a prominence, a large fraction of the emergent line photons are due to scattering of photons incident on the surface of the prominence so that one expects that in a prominence the frequency redistribution processes will play an important role in determining the emergent intensity.

Sign in / Sign up

Export Citation Format

Share Document