Variation of electromagnetic wave polarization due to resonant generation of second harmonic

We study characteristics of polarization of electromagnetic waves in the case when their second harmonic is resonantly generated in a magnetized plasma. A collisionless, homogeneous and cold plasma in a constant external magnetic field is considered. Linearly polarized electromagnetic radiation emitted by a source becomes elliptically or circularly polarized while propagating through a magnetized plasma. The polarization angle and the ratio of axes of the polarization ellipse are calculated at different distances from the source.