LINEAR-MODE COUPLING AND POLARIZATION FEATURES OF RADIATION IN CURRENT SHEETS

The plasma current sheet with a transverse component of magnetic field is analyzed as an efficient linear transformer of the electromagnetic extraordinary (X) and ordinary (O) modes. The analytical solutions an d quantitative estimates show that, under the conditions of effective X-, O-mode coupling found in the paper, the polarization features of r adio waves having passed through the sheet differ essentially from tho se calculated in the geometrical optics approximation. Thus, by means of the polarization observations, the linear X-, O-mode conversion may give the real data on the inhomogeneity and strength of the main and transverse components of magnetic field in the coupling region inside the sheet. The theory of mode coupling is applied to the calculation o f the polarization features of solar radio emission that turn out to b e well interpreted if the proper current sheet stabilized by a weak tr ansverse magnetic field is situated in the solar corona on the pathway of radio waves toward the Earth.