This paper reports verification and validation of linear simulations of Alfvén eigenmodes in the current ramp phase of DIII-D L-mode discharge #159243 using gyrokinetic, gyrokinetic-MHD hybrid, and eigenvalue codes. Using a classical fast ion profile, all simulation codes find that reversed shear Alfvén eigenmodes (RSAE) are the dominant instability. The real frequencies from all codes have a coefficient of variation of less than 5% for the most unstable modes with toroidal mode number n = 4 and 5. The simulated RSAE frequencies agree with experimental measurements if the minimum safety factor is adjusted, within experimental errors. The simulated growth rates exhibit greater variation, and simulations find that pressure gradients of thermal plasmas make a significant contribution to the growth rates. Mode structures of the dominant modes agree well among all codes. Moreover, using a calculated fast ion profile that takes into account the diffusion by multiple unstable modes, a toroidal Alfvén eigenmode (TAE) with n = 6 is found to be unstable in the outer edge, consistent with the experimental observations. Variations of the real frequencies and growth rates of the TAE are slightly larger than those of the RSAE. Finally, electron temperature fluctuations and radial phase shifts from simulations show no significant differences with the experimental data for the strong n = 4 RSAE, but significant differences for the weak n = 6 TAE. The verification and validation for the linear Alfvén eigenmodes is the first step to develop an integrated simulation of energetic particles confinement in burning plasmas incorporating multiple physical processes.
本论文报告了在DIII-D L模式放电#159159的电流爬升阶段，使用回旋动理学、回旋动理学-磁流体动力学混合以及特征值代码对阿尔芬本征模进行线性模拟的验证与确认。使用经典快离子分布，所有模拟代码均发现反剪切阿尔芬本征模（RSAE）是主导不稳定性。对于环向模数n=4和5的最不稳定模，所有代码给出的实频变异系数小于5%。模拟得到的RSAE频率与实验测量一致，前提是最小安全因子q_min经过调整，且在实验误差范围内。模拟得到的增长率差异较大，且模拟发现热等离子体压强梯度对增长率有显著贡献。各代码间主导模的模结构吻合良好。此外，使用考虑了多种不稳定模扩散作用的计算快离子分布，发现环向模数n=6的环向阿尔芬本征模（TAE）在外边界处不稳定，与实验观测一致。该TAE的实频和增长率的差异略大于RSAE。最后，对于强n=4 RSAE，模拟得到的电子温度涨落和径向相位与实验数据无显著差异；但对于弱n=6 TAE，则存在显著差异。线性阿尔芬本征模的验证与确认是发展燃烧等离子体中高能粒子约束集成模拟（包含多种物理过程）的第一步。