Energy and momentum transfer by eigenmodes in tokamaks and stellarators, which arises when eigenmodes are destabilized by superthermal ions in a region that does not coincide with the damping region, is considered. This phenomenon, named spatial channeling (SC), may play an important role in toroidal plasmas. It may affect plasma energy confinement, plasma rotation, heating of the electron and ion components, and features of eigenmodes. The work contains both an overview and new results. In particular, it is found that SC may affect structure of Toroidicity-induced Alfvén Eigenmodes (TAE modes); the analysis is carried out for a low-mode-number TAE. It is concluded that high-frequency modes, with frequencies above and around the ion cyclotron frequency (fast magnetoacoustic modes and Alfvén modes), are more likely to affect plasma energy balance for reasonable values of mode amplitudes than low-frequency Alfvén modes. SC can also have strong influence on sheared rotation for reasonable values of mode amplitudes, and this effect does not depend on mode frequency. The overview is restricted to modes naturally occurring in unstable plasmas.
Alfvén eigenmode stability and fast ion loss in DIII-D and ITER reversed magnetic shear plasmas