On the modulational instability of alfven waves in hot plasma

The modulation instability of alfven waves is considered. In a many-dimensional case the collapse takes place in a nonlinear stage. The possibility of collapse for much more low-frequency oscillations i.e. alfven waves is indicated. The alfven collapse leads to the generation of large average fields, which causes the distortion of magnetic force lines. In experiments, when intensive alfven oscillations are excited, the collapse may cause the destruction of magnetic surfaces and, obviously, the aggravation of plasma confinement. It is worth mentioning that energy dissipation of collapsing waves can be connected with intersection of particle trajectories in strong inhomogeneous oscillation fields