An Equation Of Radiative Transfer (or Radiative Transfer Equation or RTE or Transfer Equation) is an equation that describes Radiative Transfer, the transfer of energy by EMR through a gas or Plasma, taking into account factors that can remove Photons (Absorption) and can insert them (Emission). One form:
1 ∂ ^ — ——Iν + Ω˙∇Iν + (kν,s + kν,a)Iν = jν + 1/(4π) kν,s ∫IνdΩ c ∂t
Variants of the equation assume equilibrium (no change over time), an approximation of the composite of all Wavelengths (Gray Atmosphere, using the Rosseland Mean Opacity), a directional component (Eddington Approximation) and/or that variation in the medium is in a single direction (Plane-parallel Atmosphere). These are used in models of Stellar Structure.