Stability of anisotropic plasmas to almost-perpendicular magnetosonic waves

The stability of anisotropic plasmas to the magnetosonic (or right-hand compressional Alfvén) wave, near the ion cyclotron frequency, propagating almost perpendicular to the magnetic field, is investigated. For this case, and for wavelengths larger than the ion Larmor radius and for large ion plasma frequency (w²_p+ Ω^p₊) the dispersion relation is obtained in a simple form. It is shown that for T # T_' (even T T) no instabifity occurs. The resonant ters are also included, and it is shown that there is no resonant instabifity, only damping.