Publication | Open Access
On the Dependence of the Two-Level Source Function on its Own Radiation Field
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1973
Year
Two-level Source FunctionEngineeringAbsorption SpectroscopyRadiative TransferAbsorption ProfileOptical PropertiesOwn Radiation FieldComputational ElectromagneticsPhysicsRadiative AbsorptionAtomic PhysicsRadiation TransportCosmic RaySynchrotron RadiationNumerical InstabilitiesNuclear AstrophysicsDoppler RedistributionNatural SciencesLight Absorption
The consequences of the universally made assumption that the stimulated emission profile is identical to the absorption profile are quantitatively investigated for a two-level atom with Doppler redistribution. The non-linear terms arising in the source function are evaluated iteratively. We find that the magnitude of the effects are governed by ζ = (exp ( hv / kT ) − 1) −1 and are probably completely negligible for visible and UV solar lines. For ζ = 2 effects of ∼5 per cent are encountered. Larger ζ 's lead to numerical instabilities in the method of solution used.