Investigated are the effects of energetic particles (EPs), arising from off-axis neutral beam injection, on the resistive wall mode (RWM) instability in tokamaks. The analytic results for a cylindrical plasma show that EPs contribute the strongest kinetic damping to the RWM, as the deposition radius approaches the peak location of the mode eigenfunction. Toroidal computations are also carried out utilizing the MARS-K code, which includes EPs with anisotropic equilibrium distribution in the particle pitch angle space. These self-consistent numerical results confirm the analytic finding, that the RWM growth rate decreases as the peak of the EPs’ radial density profile approaches the maximum of the mode displacement. This study thus demonstrates the possibility of the RWM stabilization by the off-axis neutral beam injection in tokamak experiments.

研究了离轴中性束注入产生的高能粒子（EPs）对托卡马克中电阻壁模式（RWM）不稳定性的影响。圆柱等离子体的分析结果表明，当沉积半径接近模式本征函数的峰值位置时，EP对RWM的作用最强。还使用MARS-K代码进行环面计算，该代码包括粒子间距角空间中具有各向异性平衡分布的EP。这些自洽的数值结果证实了分析发现，即随着EPs径向密度分布的峰值接近模态位移的最大值，RWM的增长率会降低。因此，这项研究证明了在托卡马克实验中通过离轴中性束注入使RWM稳定的可能性。