The ITER Fibre Optic Current Sensor (FOCS) is a dc coupled current measurement system that will provide back-up ITER plasma current measurements using a sensing fibre located on the outer surface of the vacuum vessel. To address the impact of a harsh tokamak environment on the sensor performance we installed a FOCS system on JET and performed current measurements in various machine operating scenarios for currents up to 3 MA. Me have observed a good agreement between the FOCS and the reference Continuous External Rogowski (CER) coils data. The linearity of the FOCS response was demonstrated. The FOCS has performance characteristics compatible with the ITER requirements and in contrast to the CER is non-sensitive to magnetic crosstalk effects.

中文翻译：

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使用基于偏振测量的光纤电流传感器在 JET 上进行等离子体电流测量

ITER 光纤电流传感器 (FOCS) 是一种直流耦合电流测量系统，将使用位于真空容器外表面的传感光纤提供备用 ITER 等离子体电流测量。为了解决恶劣的托卡马克环境对传感器性能的影响，我们在 JET 上安装了 FOCS 系统，并在各种机器操作场景中进行电流测量，电流高达 3 MA。我观察到 FOCS 和参考连续外部罗戈夫斯基 (CER) 线圈数据之间有很好的一致性。 FOCS 响应的线性得到了证明。 FOCS 的性能特征符合 ITER 要求，与 CER 相比，FOCS 对磁串扰效应不敏感。