1. Chen, White, and Rosenbluth - PRL 52 (1984) 1122.

This is a fundamental work for fusion plasma physics because the concept of resonant modes is introduced and thoroughly explained. This concept goes beyond the familiar idea of plasma eigenmode excitation via wave-particle resonant interactions. It is intimately connected with the resonant mode excitation at the characteristic frequency of energetic particles, which is a ``continuum" of frequencies, parameterized by the dependencies in the particle distribution function. Evidently, resonant modes are not plasma eigenmodes and, as such, they cannot be excited in the absence of energetic particles: thus, they exist only above the excitation threshold set by the background plasma damping. In the present case, this is the internal kink mode damping due to the shear Alfvén continuum spatial resonance. The internal kink mode is resonantly excited at the precession frequency of magnetically trapped particles. This phenomenon is observed experimentally as fishbone oscillations: a remarkable example of successful theoretical explanation of complex experimental behaviors.

2. Chen - Phys. Plasmas 1 (1994) 1519.

In this work, the profound link between shear Alfvén continuous spectrum and the Energetic Particle driven continuum Modes (EPM) is fully unveiled. EPMs, as resonant modes, are naturally excited as shear Alfvén waves when resonant drive overcomes continuum damping. The theoretical prediction of EPMs is a milestone in burning plasma magnetic fusion energy research. This is the case because of the robust wave-particle resonant interaction of MeV fusion products with |v|≈V_A. EPMs are expected to be excited in the plasma core, where the energetic ion (fusion product) energy density is highest and where TAE and other discrete modes are expected to be strongly damped by continuum damping and/or ion Landau damping. The resonant character of EPMs makes them the optimal scattering mechanism for energetic ions, since modes tend to follow the particle free energy source as it is displaced. For this reason EPMs are one of the most studied topics in burning plasma physics research, both theoretically and experimentally. In this case, an important and fundamental physical phenomenon was predicted theoretically before clear experimental evidence.