A derivation of the radiative transfer equation for partially polarized light from quantum electrodynamics

✍ Scribed by Charles Acquista; James L Anderson

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 445 KB
• Volume: 106
• Category: Article
• ISSN: 0003-4916
• DOI: 10.1016/0003-4916(77)90319-0

✦ Synopsis

Corrections to the transfer equation for partially polarized light due to induced processes are considered here. A derivation of the transfer equation from the principles of quantum electrodynamics is presented, and its terms are evaluated for a Thomson scattering law.

Radiative transfer involves the calculation of changes in the intensity (rather than the amplitulde) of radiation due to absorption, emission, and scattering in the ambient medium. Mostly all of the work in this field is based on equations of transfer which are obtained heuristically rather than derived from first principles (see, e.g., [I]). For most contemporary problems, such as radiative transfer in planetary atmospheres, this theory yields sufficiently accurate results. However, the limitations ofthese heuristic equations can be uncovered and satisfactorily explained only when the equations are derived frolm basic physical principles. Thus, when more complicated problems are considered and heuristic arguments break down, we can determine the appropriate transfer equations by appealing to our derivation. One of the first such derivations was performed by Keller [2] who considered the problem of wave propagation in an atmosphere with weak fluctuations in the refractive index. By treating these fluctuations, as if they were random. he derived a transfer equation directly from the wave equal.ion. More recently. Burridge and Papanicolaou [3] obtained transfer equations for partially polarized light from Maxwell's equations by applying a perturbation scheme. For low-temperature astrophysical systems (the spectral line regime), Gelinas and Ott [4] derived radiative transfer eqtiations from the principles of quantum theory.