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

Author(s):  
Ge Dong ◽  
Zhihong Lin

Abstract The clear understanding of the wave-particle interaction and associated transport mechanism of different particle species in the drift wave instabilities is important for accurate modeling and predictions of the plasma confinement properties. Our 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 in the tokamak core. Similarly, 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, but the ion transport is mostly driven by the nonlinear wave-particle scattering in both the CTEM and ITG turbulence.

2001 ◽  
Vol 65 (3) ◽  
pp. 235-253 ◽  
Author(s):  
K. KOMOSHVILI ◽  
S. CUPERMAN ◽  
C. BRUMA

Turbulent transport of heat and particles is the principle obstacle confronting controlled fusion today. We investigate quantitatively the suppression of turbulence and formation of transport barriers in spherical tokamaks by sheared electric fields generated by externally driven radiofrequency (RF) waves, in the frequency range ωA ∼ ω < ωci (where ωA and ωci are the Alfvén and ion cyclotron frequencies).This investigation consists of the solution of the full-wave equation for a spherical tokamak in the presence of externally driven fast waves and the evaluation of the power dissipation by the mode-converted Alfvén waves. This in turn provides a radial flow shear responsible for the suppression of plasma turbulence. Thus a strongly nonlinear equation for the radial sheared electric field is solved, and the turbulent transport suppression rate is evaluated and compared with the ion temperature gradient (ITG) instability increment.


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