An ultrafast charge exchange spectroscopy (UFCES) system has been designed for measuring fluctuations in ion temperature and toroidal rotation velocity. The UFCES on the KSTAR tokamak is a powerful tool for investigating plasma instabilities and long-wavelength turbulence related to ion temperature gradient and flow. The UFCES system is designed to measure the C VI line (n = 8 → 7, λ₀ = 529.05 nm) from the charge exchange reaction between a deuterium-heating neutral beam and the intrinsic carbon impurity in KSTAR. The ion temperature and toroidal rotation velocity at two radial positions will be observed simultaneously with UFCES. The key difference between the UFCES system and conventional charge exchange spectrometers is the application of high-throughput collection optics, a high-efficiency transmission grating combined with prisms, and a high-speed detector. We use a comprehensive spectrum simulation code with input parameters of KSTAR’s plasmas and a neutral beam injection system to estimate the performance of the designed UFCES system. The results simulated with the code show that the diagnostic achieves a turbulence-relevant time resolution of 10 µs with a high enough signal-to-noise ratio. Furthermore, a preliminary test is performed using a complementary metal–oxide semiconductor camera and Ne spectral lamp to confirm the linear dispersion and curvature radius.

中文翻译：

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在 KSTAR 托卡马克上开发超快电荷交换光谱系统

超快电荷交换光谱 (UFCES) 系统已设计用于测量离子温度和环形旋转速度的波动。KSTAR托卡马克上的UFCES是研究与离子温度梯度和流量有关的等离子体不稳定性和长波湍流的有力工具。UFCES 系统设计用于测量 C VI 线 (n = 8 → 7, λ ₀= 529.05 nm）来自氘加热中性束与 KSTAR 中的固有碳杂质之间的电荷交换反应。UFCES 将同时观察两个径向位置的离子温度和环形旋转速度。UFCES 系统与传统电荷交换光谱仪之间的主要区别在于应用了高通量收集光学器件、结合棱镜的高效透射光栅和高速检测器。我们使用具有 KSTAR 等离子体输入参数和中性束注入系统的综合光谱模拟代码来估计设计的 UFCES 系统的性能。代码模拟的结果表明，诊断实现了 10 µ的湍流相关时间分辨率具有足够高的信噪比的s。此外，使用互补金属氧化物半导体相机和 Ne 光谱灯进行初步测试，以确认线性色散和曲率半径。