Southwestern Institute of Physics, Chengdu 610041, China.
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China.
Rev Sci Instrum. 2023 Mar 1;94(3):033508. doi: 10.1063/5.0099281.
The fast-ion D-alpha diagnostic (FIDA) is employed to detect Dα light emitted by neutralized fast ions during neutral beam injection. A tangentially viewing FIDA has been developed for the HuanLiuqi-2A (HL-2A) tokamak and typically achieves temporal and transverse spatial resolutions of ∼30 ms and ∼5 cm, respectively. A fast-ion tail on the red shifted wing of the FIDA spectrum is obtained and analyzed with the Monte Carlo code FIDASIM. Good agreement has been presented between the measured and simulated spectra. As the FIDA diagnostic's lines of sight intersect the central axis of neutral beam injection with small angles, the beam emission spectrum is observed with a large Doppler shift. Thus, tangentially viewing FIDA could detect only a small portion of fast ions with an energy of ≈ 20 ∼ 31 keV and a pitch angle of ≈ -1 ∼ -0.8. A second FIDA installation with oblique viewing is designed to minimize spectral contaminants.
快离子 D-α 诊断仪（FIDA）用于检测中性束注入期间中性化快离子发射的 Dα 光。一种切向观察 FIDA 已为环流器 2A（HL-2A）托卡马克开发，并通常分别实现了约 30ms 和 5cm 的时间和横向空间分辨率。通过蒙特卡罗代码 FIDASIM 获得了 FIDA 光谱的红移翼上的快离子尾部，并对其进行了分析。测量和模拟光谱之间呈现出良好的一致性。由于 FIDA 诊断的视线与中性束注入的中心轴以小角度相交，因此观察到了具有较大多普勒位移的束发射光谱。因此，切向观察 FIDA 只能检测能量约为 20-31keV 且俯仰角约为-1--0.8 的一小部分快离子。设计了第二个带有倾斜观察的 FIDA 安装装置，以最小化光谱污染物。
