Waves in cosmic magnetic structures taking into account the anisotropic plasma pressure

This paper provides an analysis of magneto-sonic eigenwaves travelling in magnetic plasma structures based on the Chew-Goldberger-Low approximation, for which the plasma kinetic pressure is different along and across the magnetic field. The anisotropy does not lead to the emergence of new modes. The dependence of phase velocities of the waves, trapped by a single magnetic surface, on the pressure anisotropy is investigated. For a magnetic slab with field-free surroundings, the dispersion relations for the eigenwaves are obtained. The pressure anisotropy may change dispersion relations of such modes significantly. In particular, backward waves are possible in the case of strong anisotropy. The dependences of the thresholds for the mirror and hose instabilities on the system parameters are obtained. In particular, hose and mirror instabilities of such waves are absent for some wave number regions. The results are used to obtain the eigenwave characteristics in coronal loops and chromospheric flux tubes.