MHD Wave Interaction within a Plasma Perturbed by Alfvén Waves

The interaction between fast magnetoacoustic waves within a plasma with periodical nonhomogeneities, perturbed by Alfvén waves has been studied. It has been ascertained the appearance of phenomena of a decay instability and an instability involving an increase of the amplitude oscillations. A study of the influence of perturbed plasma parameters on these instability phenomena has been made. It has been found that the optimal perturbing frequency for giving rise to the instability phenomenon is twice the frequency of fast magnetoacoustic waves.