Theory of Alfvén waves and energetic particle physics in burning plasmas

We present an overview on one issue of practical interest for burning plasmas, i.e. whether fast ions and charged fusion products are sufficiently well confined such that they transfer their energy and/or momentum to the thermal plasma without appreciable degradation due to collective modes. In the present work, we address this issue by analysing theoretically the dynamics of shear Alfvén waves collectively excited by energetic particles in tokamak plasmas. Both linear physics, such as spectral and stability properties, and key non-linear wave and particle dynamics are identified and considered. We also discuss the investigations of such processes via computer simulations as well as the importance of benchmarking with existing or future experimental observations.