Research for effect of nuclear elastic scattering on neutral-beam-injection plasma heating and its analysis model

基于氘、氚、氚和氚的Boltzmann-Fokker-Planck（BFP）方程，研究了中性束注入（NBI）和α粒子加热操作过程中，核弹性散射（内斯）对（a）向等离子体离子和电子的能量转移和（B）T（d，n）^4He聚变反应速率系数的影响。1.当束流注入能量大于1 MeV时，注入到离子上的NBI加热功率的增加是明显的。在低温、高密度和长约束时间下，内斯对高能离子的减速作用增强，束离子和α粒子速度分布函数中的高能分量相对较小。在这种情况下，内斯效应对离子的部分能量沉积几乎不起作用。相反，对于低密度和短约束时间，内斯效应是显着的。当n_e ≥ 4×10^<19>m^<-3>，τ_E ≥ 3 sec，T= 20 keV时，对1.5 MeV的NBI（3.5MeV α粒子）加热的增强程度接近9（4）%。相反，中性束注入的结果是在几百keV能量范围内出现了比α粒子大1 &lt;$2个数量级的拖尾。BFP计算表明，注入束流对T（d，n）^4He反应速率系数的内斯效应取决于等离子体条件。当P_<NBI>= 20 MW，E_<NBI>= 1 MeV，τ_E=3sec，T_e= 20 keV时，T（d，n）^4He反应速率系数的增强程度达到约7（3）%（n_e=2（4）×10^<19>m^）<-3>。

The effects of nuclear elastic scattering (NES) on (a) energy transfer to plasma ions and electrons and (b) T(d,n)^4He fusion reaction rate coefficient, during neutral beam injection (NBI) and α-particle heating operations, are examined on the basis of the Boltzmann-Fokker-Planck (BFP) equations for deuteron, triton, beam ion and α-particle in deuterium-tritium (DT) thermonuclear plasmas.1.The enhancement in the fraction of the NBI heating power deposited to ions becomes appreciable when beam-injection energy is larger than 1 MeV. For low temperatures, high densities and long confinement times, the slowing down of an energetic ion by NES is intensified, and thus the energetic components in beam-ion and α-particle velocity distribution functions are relatively small. In such a case, the NES effect on fractional energy deposition to ions is hardly to appear. On the contrary for low densities and short confinement times, the NES effect is significant. When n_e【greater than or equal】4×10^<19> m^<-3>, τ_E【greater than or equal】3 sec and T=20keV, the degree of the enhancement is almost 9(4) % for 1.5-MeV NBI (3.5MeV α-particle) heating.2.Owing to the NES by fusion-produced α-particle knock-on tail is formed at 〜MeV energy range in fuel-ion distribution function. On the contrary, as a result of neutral-beam injection, 1〜2 orders large tail compared with those by α-particle appears in hundreds-keV energy range. The BFP calculation shows that the NES effect caused by injected beam on T(d,n)^4He reaction rate coefficient can be appreciable depending on plasma conditions. When P_<NBI>=20MW, E_<NBI>=1MeV,τ_E=3sec and T_e=20keV, the degree of the enhancement in T(d,n)^4He reaction rate coefficient reaches by about 7(3)% for n_e=2(4)×10^<19>m^<-3>.