Accession Number : AD0468719

Title :   VALIDITY OF THE EDDINGTON APPROXIMATION TO THE RADIATIVE TRANSPORT EQUATION,

Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV

Personal Author(s) : Kulander, John L.

Report Date : JUL 1965

Pagination or Media Count : 20

Abstract : The mean intensity of the radiation field, J, is calculated assuming various LTE and non-LTE source functions using both the exact expressions and the Eddington approximation, for planeparallel geometries. The results are used to determine the maximum error encountered in using the Eddington approximation and the optical depth where the maximum error occurs in layers of various thicknesses. It is found that by assuming the Krook modification of the surface boundary conditions the maximum error to be encountered is generally less than 10-15% as long as the total optical thickness of the layer is greater than or approximately unity. (Author)

Descriptors :   (*ASTROPHYSICS, LINE SPECTRA), DIFFERENTIAL EQUATIONS, STATISTICAL ANALYSIS, ALBEDO(ASTRONOMY), PLASMAS(PHYSICS).

Distribution Statement : APPROVED FOR PUBLIC RELEASE