Conway N J, De Bock M F M, Michael C A, Walsh M J, Carolan P G, Hawkes N C, Rachlew E, McCone J F G, Shibaev S, Wearing G
EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
Rev Sci Instrum. 2010 Oct;81(10):10D738. doi: 10.1063/1.3494254.
A motional Stark effect (MSE) diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of ∼2.5 cm, and time resolution of ∼1 ms at angular noise levels of ∼0.5°. Conventional (albeit very narrow) interference filters isolate π or σ polarized emission. Avalanche photodiode detectors with digital phase-sensitive detection measure the harmonics of a pair of photoelastic modulators operating at 20 and 23 kHz, and thus the polarization state. The π component is observed to be significantly stronger than σ, in reasonably good agreement with atomic physics calculations, and as a result, almost all channels are now operated on π. Trials with a wide filter that admits the entire Stark pattern (relying on the net polarization of the emission) have demonstrated performance almost as good as the conventional channels. MSE-constrained equilibrium reconstructions can readily be produced between pulses.
一种运动斯塔克效应（MSE）诊断设备现已安装在MAST球形托卡马克装置上并常规运行，它有35个径向通道，空间分辨率约为2.5厘米，在角噪声水平约为0.5°时时间分辨率约为1毫秒。传统的（尽管非常窄）干涉滤光片可分离π或σ偏振发射。带有数字相敏检测的雪崩光电二极管探测器测量一对以20千赫和23千赫运行的光弹调制器的谐波，从而确定偏振态。观察到π分量明显强于σ分量，这与原子物理计算结果相当吻合，因此现在几乎所有通道都在π模式下运行。使用允许整个斯塔克谱型通过的宽滤光片（依赖发射的净偏振）进行的试验表明，其性能几乎与传统通道一样好。在脉冲之间可以很容易地进行受MSE约束的平衡重建。
