The aim of the study is to analyze the stability of the Energetic Particle Modes (EPM) and Alfven Eigenmodes (AE) in Helitron J and LHD plasma if the electron cyclotron current drive (ECCD) is applied. The analysis is performed using the code FAR3d that solves the reduced MHD equations describing the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particle (EP) species, including the effect of the acoustic modes. The Landau damping and resonant destabilization effects are added via the closure relation. The simulation results show that the n=1 EPM and n=2 Global AE (GAE) in Heliotron J plasma can be stabilized if the magnetic shear is enhanced at the plasma periphery by an increase (co-ECCD injection) or decrease (ctr-ECCD injection) of the rotational transform at the magnetic axis iota0. In the ctr-ECCD simulations, the EPM/AE growth rate decreases only below a given iota0, similar to the ECCD intensity threshold observed in the experiments. In addition, ctr-ECCD simulations show an enhancement of the continuum damping. The simulations of the LHD discharges with ctr-ECCD injection indicate the stabilization of the n=1 EPM, n=2 Toroidal AE (TAE) and n=3 TAE, caused by an enhancement of the continuum damping in the inner plasma leading to a higher EP beta threshold with respect to the co- and no-ECCD simulations.

中文翻译：

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ECCD 注入效应对 Heliotron J 和 LHD 等离子体稳定性的建模

该研究的目的是分析在应用电子回旋电流驱动 (ECCD) 的情况下 Helitron J 和 LHD 等离子体中高能粒子模式 (EPM) 和阿尔芬本征模式 (AE) 的稳定性。使用代码 FAR3d 进行分析，该代码求解描述全 3D 系统中极向通量和涡量的环向分量的线性演化的简化 MHD 方程，再加上高能粒子的密度方程和平行速度矩 (EP ) 物种，包括声学模式的影响。Landau 阻尼和共振失稳效应是通过闭合关系添加的。模拟结果表明，如果通过增加（co-ECCD 注入）或减少（ctr- ECCD 注入）在磁轴 iota0 处的旋转变换。在 ctr-ECCD 模拟中，EPM/AE 增长率仅低于给定的 iota0，类似于实验中观察到的 ECCD 强度阈值。此外，ctr-ECCD 模拟显示了连续阻尼的增强。使用 ctr-ECCD 注入的 LHD 放电模拟表明 n=1 EPM、n=2 环形 AE (TAE) 和 n=3 TAE 的稳定性，这是由于内部等离子体中连续阻尼的增强导致的相对于 co-ECCD 和非 ECCD 模拟，EP beta 阈值更高。