Lutsenko V. Collective phenomena in plasmas with energetic ions in tokamaks and stellarators

A new phenomenon - spatial channelling of the energy and momentum of energetic ions during plasma instabilities driven by these ions is discovered. This phenomenon can strongly affect the plasma energy balance. It also affects plasma rotation and concomitant frequency chirping of the destabilized waves. New kinds of eigenmodes and new features of the known modes in toroidal systems are found. In particular, drift-sound modes and a new kind of drift-Alfven modes are predicted. New resonances of the wave-particle interaction are revealed, which play the main role in the destabilization of the Mirror induced Alfven Eigenmodes (MAE) and Helicity induced Alfven Eigenmodes (HAE). It is found that there exist fishbone modes with frequencies well exceeding the frequency of the conventional fishbone instability. It is shown that plasma instabilities driven by the energetic ions can strongly enhance the electron heat transport across the magnetic field. Two mechanisms of this influence are revealed: first, heat conductivity and, second, heat convection caused by the waves. A new mechanism of the energetic-ion transport during sawtooth oscillations in tokamaks is revealed, and numerical modeling of effects of these oscillations on the energetic ions in tokamaks is carried out. It is found that the crashes of sawtooth oscillations can lead to sharp bursts of fusion power. Numerical codes for investigation of eigenmodes, excitation of instabilities in stellarators, transport of energetic ions during sawtooth crashes, and thermonuclear burn in plasmas with sawtooth oscillations were developed.