A Method of Knock-on Tail Observation Accounting Temperature Fluctuation Using ⁶Li+T/D+T Reaction in Deuterium Plasma

It is important to understand the phenomena occurring in nuclear burning plasmas in order to operate fusion reactors. Although multiple studies have been conducted on nuclear elastic scattering (NES), only few experiments have focused on the observation of a knock-on tail via NES in nuclear burning plasmas. NES is an important phenomenon because it occurs in various plasmas and affects their energy balance. As for the observation of a knock-on tail, a method using γ-rays/neutrons generated from ⁶Li + d^{→7 -}Li* + p, ⁶Li + d^{→ 7}Be* + n, or D + d^→3He + n reactions in a proton-beam-injected deuterium plasma has been proposed. However, there is a possibility to be unable to distinguish whether the main factor affecting the reaction rates is the plasma temperature or the formation of a knock-on tail. To avoid this confusion, herein, we proposed a method based on ⁶Li + t^→8Li* + p or D + t^→4He + n reactions. These reactions can reveal the plasma temperature without the influence of a knock-on tail because the triton distribution function in deuterium plasmas is remarkably distorted from Maxwellian. The procedure and utilization possibility of the proposed method are discussed.