The absorption coefficients for extraordinary and ordinary electromagnetic modes are found for a tenuous hot magnetized plasma, taking into account the collisions between plasma particles and the scattering of photons. An approach is suggested which generalizes 'collisionless' and 'cold-plasma' approximations. The simple formulae obtained are valid both near, and at a distance from, the cyclotron harmonics. In particular, the ordinary mode is shown to have resonance at the cyclotron frequency. The number of noticeable reasonances of absorption coefficient at cyclotron harmonics is estimated for both modes. Using the coefficients obtained, the intensity, Stokes parameters and polarization of radiation of a homogeneous plasma slab are calculated for conditions which may be realized in the heated regions of accreted plasma in an AM Herculis-type system. The large difference between the absorption coefficient of extra-ordinary and ordinary modes near the cyclotron harmonics may result in the emission of the broad polarized continuum together with the narrow cyclotron lines. The polarization of these lines has a complicated spectral dependence. The results obtained are shown to be useful for explaining the main properties of AM Herculistype objects.
All Science Journal Classification (ASJC) codes
Astronomy and Astrophysics
Space and Planetary Science