The successful application of three-dimensional (3D) magnetohydrodynamic (MHD) spectroscopy enables us to identify the multi-mode eigenvalues in DIII-D and KSTAR tokamak experiments with stable plasmas. The temporal evolution of the multi-modes’ stabilities have been detected. The new method is numerically efficient allowing the real time detection of MHD modes’ stabilities during the discharge. The method performs active detection of the plasma stability by utilizing the upper and lower rows of internal non-axisymmetric coils to apply a wide variety of 3D fields. Multi-mode eigenvalues are extracted using subspace system identification of the plasma response measured by 3D-field magnetic sensors distributed at different poloidal locations. The equivalence of this new method with the one introduced by Wang (2019 Nucl. Fusion 59 024001) has been numerically corroborated. The more robust and efficient calculation developed here will enable real time monitoring of the plasma stability based on the extracted eigenvalues of stable modes.

三维 (3D) 磁流体动力学 (MHD) 光谱的成功应用使我们能够在稳定等离子体的 DIII-D 和 KSTAR 托卡马克实验中识别多模式特征值。已检测到多模式稳定性的时间演变。新方法在数值上是有效的，允许在放电过程中实时检测 MHD 模式的稳定性。该方法通过利用上下两排内部非轴对称线圈应用各种 3D 场来主动检测等离子体稳定性。使用分布在不同极向位置的 3D 场磁传感器测量的等离子体响应的子空间系统识别来提取多模式特征值。这种新方法与 Wang (2019) 介绍的方法的等效性核。Fusion 59 024001) 已得到数字证实。此处开发的更稳健、更有效的计算将能够基于提取的稳定模式的特征值实时监测等离子体稳定性。