Charge exchange spectroscopy has been widely used in fusion devices to measure ion temperature, and toroidal and poloidal flow velocities of plasma. For local measurement, especially in the core region of the plasma, the spectrum emitted by the charge exchange reaction between the main plasma ions or impurity ions and the intentionally injected neutral beam should be analyzed so that parameters can be accurately deduced. Since the line-integrated spectrum signal through the line of sight of the diagnostic optics usually contains an unnecessary overlapped spectrum signal, referred to as the background signal, that typically originates from the plasma boundary region, a beam modulation technique is commonly applied to separate the background signal from the measured spectrum. Recently, it has been demonstrated in the KSTAR tokamak that a two-Gaussian fitting (TGF) method can be applied to analyze the spectrum and deduce plasma ion temperature and toroidal rotation velocity profiles of reasonable accuracy without beam modulation. It has been realized that the measurement result by the TGF method can be alternatively used to investigate plasma transport dynamics when beam modulation is prohibited to avoid any possible disturbance inhibiting robust plasma control and stable operation of the neutral beam injection system.

电荷交换光谱已广泛用于聚变设备中，以测量离子温度以及等离子体的环面和倍性流速。对于局部测量，尤其是在等离子体的核心区域，应分析由主要等离子体离子或杂质离子与有意注入的中性束之间的电荷交换反应所发射的光谱，以便可以准确推导参数。由于通过诊断光学系统的视线进行的线积分光谱信号通常包含不必要的重叠光谱信号（称为背景信号），通常源于等离子体边界区域，因此通常使用束调制技术来分离被测光谱的背景信号。最近，在KSTAR托卡马克中已证明，可以采用两高斯拟合（TGF）方法来分析光谱，并推导出合理准确度的等离子体离子温度和环向旋转速度曲线，而无需进行束调制。已经认识到，当禁止束调制时，通过TGF方法的测量结果可以替代地用于研究等离子体传输动力学，以避免任何可能的干扰，该干扰抑制了稳健的等离子体控制和中性束注入系统的稳定运行。