The helicity of a photon traversing a magnetized plasma can flip when the
B-field along the trajectory slowly reverses. Broderick and Blandford have
recently shown that this intriguing effect can profoundly change the usual
Faraday effect for radio waves. We study this phenomenon in a formalism
analogous to neutrino flavor oscillations: the evolution is governed by a
Schroedinger equation for a two-level system consisting of the two photon
helicities. Our treatment allows for a transparent physical understanding of
this system and its dynamics. In particular, it allows us to investigate the
nature of transitions at intermediate adiabaticities.Comment: 8 pages, 2 eps figures, and a note added. Title changed. Matches
published versio
