The magnetic diagnostic system at the optimized stellarator experiment Wendelstein 7-X (W7-X) includes a total number of 125 Mirnov coils, which are mounted at the inner plasma vessel wall. A wide range of expected signal amplitudes, frequencies and mode numbers is covered to account for the complex three-dimensional geometry of W7-X. The performed amplitude and phase calibration of individual coils including all relevant data acquisition system components allows a detailed spectral and mode analysis. The damped multiple signal classification method and stochastic system identification techniques are shortly described and applied. Two observations are emphasized within this work. Firstly, independent of magnetic configuration and heating scenario (electron cyclotron resonance heating and/or neutral beam injection), broadband fluctuations around 180 kHz have been measured. The nature of these fluctuations is possibly associated with ellipticity-induced Alfvn eigenmodes in the outer regions of the plasma. The latter was inferred by studying corresponding theoretically predicted Alfvn continua calculated with the 3D-MHD continuum code CONTI. Secondly, fast collapses of plasma current and energy, which occurred during recent operational phases at W7-X, show a clear magnetic signature. Short time scale Alfvnic bursts are revealed, which are induced during these sawtooth-like collapses.

优化的恒星器实验Wendelstein 7-X（W7-X）上的磁诊断系统包括总共125个Mirnov线圈，这些线圈安装在内部等离子体容器壁上。涵盖了广泛的预期信号幅度，频率和模式编号，以解决W7-X的复杂三维几何形状。对包括所有相关数据采集系统组件的单个线圈执行的幅度和相位校准可以进行详细的频谱和模式分析。简要描述和应用了阻尼多信号分类方法和随机系统识别技术。在这项工作中强调了两个观察结果。首先，独立于磁配置和加热方案（电子回旋共振加热和/或中性束注入），已经测量了大约180 kHz的宽带波动。这些波动的性质可能与在等离子体外部区域中由椭圆率引起的Alfvn本征模式有关。后者是通过研究用3D-MHD连续体代码CONTI计算的相应理论上预测的Alfvn连续体来推断的。其次，在W7-X最近的运行阶段中发生的等离子体电流和能量的快速崩溃显示出明显的磁信号。揭示了短时间尺度的Alfvnic爆发，这些爆发是在这些锯齿状坍塌过程中引起的。后者是通过研究用3D-MHD连续体代码CONTI计算的相应理论上预测的Alfvn连续体来推断的。其次，在W7-X最近的运行阶段中发生的等离子体电流和能量的快速崩溃显示出明显的磁信号。揭示了短时间尺度的Alfvnic爆发，这些爆发是在这些锯齿状坍塌过程中引起的。后者是通过研究用3D-MHD连续体代码CONTI计算的相应理论上预测的Alfvn连续体来推断的。其次，在W7-X最近的运行阶段中发生的等离子体电流和能量的快速崩溃显示出明显的磁信号。在这些锯齿状坍塌过程中诱发了短时标的Alfvnic爆发。