Magnetohydrodynamic (MHD) instabilities are widely observed during tokamak plasma operation. Magnetic diagnostics provide important information which supports the understanding and control of MHD instabilities. This paper presents the current status of the magnetic diagnostics dedicated to measuring MHD instabilities at the J-TEXT tokamak; the diagnostics consist of five Mirnov probe arrays for measuring high-frequency magnetic perturbations and two saddle-loop arrays for low-frequency magnetic perturbations, such as the locked mode. In recent years, several changes have been made to these arrays. The structure of the probes in the poloidal Mirnov arrays has been optimized to improve their mechanical strength, and the number of in-vessel saddle loops has also been improved to support better spatial resolution. Due to the installation of high-field-side (HFS) divertor targets in early 2019, some of the probes were removed, but an HFS Mirnov array was designed and installed behind the targets. Owing to its excellent toroidal symmetry, the HFS Mirnov array has, for the first time at J-TEXT, provided valuable new information about the locked mode and the quasi-static mode (QSM) in the HFS. Besides, various groups of magnetic diagnostics at different poloidal locations have been systematically used to measure the QSM, which confirmed the poloidal mode number m and the helical structure of the QSM. By including the HFS information, the 2/1 resonant magnetic perturbation (RMP)-induced locked mode was measured to have a poloidal mode number m of ∼2.

在托卡马克等离子体操作过程中广泛观察到磁流体动力学 (MHD) 不稳定性。磁诊断提供重要信息，支持理解和控制 MHD 不稳定性。本文介绍了专用于测量 J-TEXT 托卡马克 MHD 不稳定性的磁诊断的现状；诊断包括五个用于测量高频磁扰动的 Mirnov 探针阵列和两个用于低频磁扰动（例如锁定模式）的鞍形环阵列。近年来，对这些阵列进行了一些更改。极向 Mirnov 阵列中的探针结构已经过优化以提高其机械强度，并且还改进了血管内鞍形环的数量以支持更好的空间分辨率。由于在 2019 年初安装了高场侧 (HFS) 偏滤器目标，因此拆除了一些探头，但在目标后面设计并安装了 HFS Mirnov 阵列。由于其出色的环形对称性，HFS Mirnov 阵列首次在 J-TEXT 上提供了有关 HFS 中锁定模式和准静态模式 (QSM) 的宝贵新信息。此外，在不同极向位置的各种磁诊断已被系统地用于测量 QSM，从而证实了极向模式数 提供了有关 HFS 中锁定模式和准静态模式 (QSM) 的有价值的新信息。此外，在不同极向位置的各种磁诊断已被系统地用于测量 QSM，从而证实了极向模式数 提供了有关 HFS 中锁定模式和准静态模式 (QSM) 的有价值的新信息。此外，在不同极向位置的各种磁诊断已被系统地用于测量 QSM，从而证实了极向模式数m和 QSM 的螺旋结构。通过包含 HFS 信息，2/1 谐振磁扰 (RMP) 诱导的锁定模式被测量为具有~2的极向模式数m。