view Abstract Citations (28) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Angle-dependent frequency redistribution in a plane-parallel medium - External source case Lee, J. -S. ; Meier, R. R. Abstract A model of partial frequency redistribution for resonant scattering in a plane-parallel, optically thick atmosphere has been developed, which exactly takes into account the angular dependence of the redistribution function. The excitation source is assumed to be a continuum, external to the medium. A Monte Carlo method is employed to simulate the scattering of photons by two-level Maxwell-Boltzmann atoms with discrete lower atomic states and broadened upper states. Media with line center optical depths of up to one-million are considered. None of the standard approximations of radiative transport theory (e.g., angle-averaged partial redistribution, complete frequency redistribution, or monochromatic scattering) could exactly reproduce the line profiles, although good representations of the frequency-integrated emission rates are found in various regimes. An unexpected depletion of photons in the near wings of backscattered emission lines from very optically thick media, which are found in earlier work, has been verified. Its presence suggests the possibility of direct measurement of the redistribution function. Publication: The Astrophysical Journal Pub Date: August 1980 DOI: 10.1086/158222 Bibcode: 1980ApJ...240..185L Keywords: Atmospheric Models; Atmospheric Scattering; Distribution Functions; Frequency Distribution; Optical Thickness; Resonance Scattering; Albedo; Angles (Geometry); Mathematical Models; Maxwell-Boltzmann Density Function; Monte Carlo Method; Photon Density; Radiative Transfer; Optics full text sources ADS |