Speaker
Description
Sawtooth oscillations are one of the important MHD instabilities in tokamak plasmas. Previous studies have shown that they have different complex dynamic behaviors, which have important implications for the performance of fusion reactors. Energetic particles are believed to affect MHD instabilities and plasma confinement through various mechanisms, such as inducing zonal flows by redistributing themselves. We conducted a simulation study on the interaction between energetic particles and sawtooth oscillations using the CLT-K code. We found that nonlinear sawtooth oscillations would cause energetic particles to escape from the central core region and to accumulate in the vicinity of the q=1 rational surface, which has a stabilizing effect on the sawtooth oscillations, making the oscillation amplitude gradually smaller and even approaching a steady state. However, the accumulation of energetic particles near the q=1 rational surface could generate the n=0 zonal flow that could lead to the re-excitation of the sawtooth oscillation, causing more significant sawtooth oscillations. Furthermore, this study explored the influence of the viscosity, the resistivity, and the energetic particle distribution on the stability and re-excitation of sawtooth oscillations, providing a new perspective for understanding the interaction mechanism between sawtooth oscillations and energetic particles and exploring methods for controlling sawtooth oscillations using neutral beam injection, etc.
| Presentation type | Oral |
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