We investigate analytically the effects of energetic particles (EPs) on the instability of the density-gradient-driven collisionless trapped electron mode (CTEM) through linear gyrokinetic theory and bounce kinetic theory in tokamak plasmas. The effects of EPs, including fusion-born alpha particles and neutral-beam-injection-driven beam ions, on the CTEM instability are compared for the dynamic model with slowing-down (SD) and equivalent Maxwellian (EM) equilibrium EP distribution functions and dilution model. It is found that the density-gradient-driven CTEM instability in the long wavelength regime can be further destabilized by EPs mainly due to the downshift in the real frequency of the mode by dilution effects. This is attributed to more resonant electrons around the smaller phase velocity of the drift wave and the consequent stronger excitation of CTEM instability. The growth rate is slightly higher for the dilution model as compared to that for the dynamic model since the Landau damping effects of EPs are neglected in the dilution model. Moreover, there is no significant difference in the growth rate between the cases of SD and EM equilibrium EP distribution functions, except for the case of alpha particles and with relatively higher electron temperature.

我们通过托卡马克等离子体中的线性陀螺动力学理论和弹跳动力学理论分析了高能粒子 (EP) 对密度梯度驱动的无碰撞俘获电子模式 (CTEM) 不稳定性的影响。对于具有减速 (SD) 和等效麦克斯韦 (EM) 平衡 EP 分布函数的动态模型，比较了 EP（包括融合产生的 α 粒子和中性束注入驱动的束离子）对 CTEM 不稳定性的影响，以及稀释模型。研究发现，长波长区域中密度梯度驱动的 CTEM 不稳定性可能会被 EP 进一步破坏，这主要是由于稀释效应导致模式的实际频率下降。这归因于漂移波的较小相速度周围有更多的共振电子以及随之而来的 CTEM 不稳定性的更强激发。与动态模型相比，稀释模型的增长率略高，因为在稀释模型中忽略了 EP 的朗道阻尼效应。此外，除了α粒子和电子温度相对较高的情况外，SD和EM平衡EP分布函数的情况之间的增长率没有显着差异。