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Astron. Astrophys. 350, 327-333 (1999)

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Partial frequency redistribution with Hanle and Zeeman effects

Non-perturbative classical theory

V. Bommier 1 and J.O. Stenflo 2

1 Laboratoire `Atomes et Molécules en Astrophysique', CNRS UMR 8588 - DAMAp, Observatoire de Paris, Section de Meudon, F-92195 Meudon, France (Veronique.Bommier@obspm.fr)
2 Institute of Astronomy, ETH Zentrum, CH-8092 Zürich, Switzerland (stenflo@astro.phys.ethz.ch)

Received 8 June 1999 / Accepted 6 August 1999


A theory for the scattering of polarized radiation with partial frequency redistribution and coherence effects in the presence of magnetic fields of arbitrary strength and direction is developed within a classical framework. The time-dependent equation for a classical oscillator is solved. While the oscillator is being excited, it is also damped by emission of radiation and subject to phase-destroying collisions. Fourier transformation of the emitted wave train with phase-scrambling collisions leads to the partial-redistribution expressions for the relation between the polarization and frequencies of the incident and scattered radiation. While previous treatments of partial redistribution have been based on quantum perburbation theory, the classical theory has the advantage of being fully non-perturbative. It is therefore conceptually more transparent and leads itself to direct physical interpretation. The classical and quantum theories give identical results for a [FORMULA] transition.

Key words: atomic processes – line: formation – scattering – polarization – magnetic fields – radiative transfer

© European Southern Observatory (ESO) 1999

Online publication: September 24, 1999