Non-LTE transfer. V - The asymptotics of partial redistribution
Abstract
The large-scale behavior of noncoherent radiative transfer with partial frequency redistribution is examined. Scaling laws for four basic scattering processes are extracted from an asymptotic analysis of the integral equation for the source function in the limit, epsilon approaches zero (where epsilon is the probability of photon destruction) to describe the dependence of characteristic lengths and frequencies on epsilon. It is shown that partial frequency redistribution simplifies drastically for small epsilon and angular redistribution is irrelevant in all cases. For all scattering processes the source function, after the rescaling of optical depths and frequencies, depends on fewer variables than the original source functions. The main results are discussed with reference to implications for numerical methods currently used in the astrophysical literature.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1980
- Bibcode:
- 1980A&A....83..166F
- Keywords:
-
- Astrophysics;
- Asymptotic Methods;
- Frequency Distribution;
- Incoherent Scattering;
- Nonequilibrium Thermodynamics;
- Radiative Transfer;
- Diffusion Theory;
- Distribution Functions;
- Doppler Effect;
- Scaling Laws;
- Singular Integral Equations;
- Transfer Functions;
- Astrophysics