Flux-limited diffusion in a scattering medium

Fulvio Melia, Gregory J. Zylstra

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We present a diffusion equation (FDT) with a coefficient that reduces to the appropriate limiting form in the streaming and near thermodynamic limits for a moving fluid in which the dominant source of opacity is Thomson scattering. This expression, derived from the general diffusion theory of Levermore & Pomraning and Pomraning, is fully flux-limited, and is useful for the radiative-hydrodynamical simulation of scattering media such as accretion-disk coronae. We compare our results to those obtained with the corresponding equations for an absorptive medium, and we show that the flux can differ by a large factor (≫ 1) between the two, depending on the temperature profile within the atmosphere. A direct comparison of our equations with exact solutions of the transfer equation suggests that FDT for a scattering medium is accurate to better than ≲ 17% over the range of optical depths 0 ≲τ ≲ 3.

Original languageEnglish (US)
Pages (from-to)732-740
Number of pages9
JournalAstrophysical Journal
Volume374
Issue number2
StatePublished - Jun 20 1991
Externally publishedYes

Fingerprint

scattering
diffusion theory
Thomson scattering
opacity
accretion disks
temperature profile
temperature profiles
optical thickness
optical depth
coronas
corona
thermodynamics
accretion
atmospheres
fluid
atmosphere
fluids
coefficients
simulation

Keywords

  • Diffusion
  • Radiative transfer
  • Stars: accretion
  • Stars: binaries
  • Stars: coronae

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Flux-limited diffusion in a scattering medium. / Melia, Fulvio; Zylstra, Gregory J.

In: Astrophysical Journal, Vol. 374, No. 2, 20.06.1991, p. 732-740.

Research output: Contribution to journalArticle

Melia, F & Zylstra, GJ 1991, 'Flux-limited diffusion in a scattering medium', Astrophysical Journal, vol. 374, no. 2, pp. 732-740.
Melia, Fulvio ; Zylstra, Gregory J. / Flux-limited diffusion in a scattering medium. In: Astrophysical Journal. 1991 ; Vol. 374, No. 2. pp. 732-740.
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