Marchenko V. Linear and nonlinear phenomena during interaction of particles and waves in plasmas of toroidal devices.

In the thesis a new kind of the alpha-particle stochastic diffusion in optimized stellarators has been discovered, which arises due to successive crossings by particle of the separatrix between locally trapped and locally passing states of the motion. Self-consistent model for the transport barrier triggering during fishbone activity has been developed. Theory of the energetic ion (both toroidally trapped and passing) effect on sawtooth oscillations in conventional tokamaks and spherical tori has been extended. Model for nonlinear resonant effect of the energetic ions on the neoclassical tearing modes has been developed. Magnetic reconnection during fishbone activity in plasmas has been explained. Theory of the circulating-ion-driven fishbones in both low-shear and reversed-shear discharges has been developed. Model for nonlinear dynamics of the zonal flow excited by short-wavelength turbulence near the modulational instability threshold has been developed. Excitation of the toroidal Alfven eigenmodesin Ohmic discharges (i.e. in the absence of energetic particles) has been explained. Resonant effect of the small-scale turbulence on the macroscopic rotating magnetic island has been revealed. Collisional damping of the Alfven eigenmodes on localized electrons in stellarators has been calculated. Mechanism for excitation of the geodesic acoustic mode during ion cyclotron resonance heating has been revealed.