The IDSA and the homogeneous sphere : Issues and possible improvements
| Autor: | Jérôme Michaud |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Coupling
Computer science Beräkningsmatematik Applied Mathematics Isotropy Computational mathematics 01 natural sciences 65Z05 35B40 35Q85 85A25 41A25 010101 applied mathematics Computational Mathematics Astrophysics - Solar and Stellar Astrophysics Astronomi astrofysik och kosmologi Homogeneous 0103 physical sciences Radiative transfer Discrete Mathematics and Combinatorics Applied mathematics Astronomy Astrophysics and Cosmology Numerical tests Mathematics - Numerical Analysis 0101 mathematics Diffusion limit 010303 astronomy & astrophysics Physics - Computational Physics Analysis |
| Popis: | In this paper, we are concerned with the study of the Isotropic Diffusion Source Approximation (IDSA) (Baxter et al., Phys. Rev. E 73, 046118, 2006) of radiative transfer. After having recalled well-known limits of the radiative transfer equation, we present the IDSA and adapt it to the case of the homogeneous sphere. We then show that for this example the IDSA suffers from severe numerical difficulties. We argue that these difficulties originate in the min-max switch coupling mechanism used in the IDSA. To overcome this problem we reformulate the IDSA to avoid the problematic coupling. This allows us to access the modeling error of the IDSA for the homogeneous sphere test case. The IDSA is shown to overestimate the streaming component, hence we propose a new version of the IDSA which is numerically shown to be more accurate than the old one. Analytical results and numerical tests are provided to support the accuracy of the new proposed approximation. Comment: 25 pages, 8 figures, accepted for publication in DCDS-S |
| Databáze: | OpenAIRE |
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