Observation Scenario of Knock-on Tail Shape Using Doppler-Broadening

It is well known that the influence of nuclear force, e.g., nuclear elastic scattering (NES), appears in an ion scattering process when ion energy increases. NES caused by high-energy particles forms the non-Maxwellian component in the ion distribution function. The non-Maxwellian component is named knock-on tail. The knock-on tail gives various effects on fusion plasma. Therefore, it is important to conduct an experiment in order to understand the impact of the NES effects. The NES effects are affected by the “shape and size” of the knock-on tail and the “shape and size” of the knock-on tail depends on plasma conditions. Therefore, we newly propose the method to observe the correlation between the NES effects and the plasma conditions by using Doppler effects for the γ-ray-generating reaction, i.e.,
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Li(d, p)
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Li nuclear reaction, in ITER-like deuterium plasma. We can capture the impact of the NES effect caused by the change in the plasma conditions, i.e., electron temperature, deuteron density, proton beam power, and proton beam energy by capturing the change in the γ-ray spectrum. On the basis of the Boltzmann-Fokker-Planck model, we showed the validity of the method by simulation.