Role of wave-particle resonance in turbulent transport in toroidal plasmas

Abstract

A clear understanding of wave-particle interaction and associated transport mechanisms of different particle species in the drift wave instabilities is important for accurate modeling and predictions of plasma confinement properties in tokamaks. In particular, the roles of linear resonance and nonlinear scattering in turbulent transport need to be delineated when constructing reduced transport models. First-principle, global gyrokinetic simulations find that electron particle and heat transport decreases to a very low level, while ion heat transport level has no dramatic change when wave-particle resonance is suppressed in the collisionless trapped electron mode (CTEM) turbulence. On the other hand, ion heat transport in the self-consistent ion temperature gradient (ITG) turbulence simulation is qualitatively similar to that in the test-particle simulation using the static ITG turbulence fields. These simulation results show that electron transport is primarily driven by the wave-particle resonance in the CTEM turbulence, and the ion transport is mostly driven by the nonlinear wave-particle scattering in both the CTEM and ITG turbulence.