Concerning a constant source function method of radiative transfer.
Abstract
The author revisits the derivation of the escape probability method of radiative transfer (EPM) and shows (1) that the usual procedure of taking the source function through the integral for the specific intensity leads, in the first instance, to an approximation (to be referred to as the constant source function method) wherein the net radiative bracket p(r) is equated to the net radiative bracket for a constant source function p^{csf}(r), and (2) that the EPM subsequently follows when the escape probability P_{e}(r) is substituted as an alternative label for p^{csf}(r). The author examines the merit of this latter substitution, including the historical reasons for its use, and concludes that there is no compelling reason to make such a substitution.
 Publication:

Journal of Quantitative Spectroscopy and Radiative Transfer
 Pub Date:
 April 1991
 DOI:
 10.1016/00224073(91)90056V
 Bibcode:
 1991JQSRT..45..217I
 Keywords:

 Energy Absorption;
 Photons;
 Radiative Transfer;
 Atomic Energy Levels;
 Doppler Effect;
 Thermodynamics and Statistical Physics