高速核在高温热平衡等离子体中的非平衡弛豫过程对热核反应率参数的影响

高速核入射到高温热平衡等离子体背景中,由于入射核动能远大于背景等离体中带电粒子之平均动能,入射核在与背景等离子体达到热平衡之前,会存在一段逐渐损失能量的非平衡弛豫过程。本文以高速氘核入射到高温氘化锂等离子体为例,在计及氘核的这种非平衡弛豫过程时,给出了一种计算热核反应D(t,n)~4He之反应率参数的方法。氘核在弛豫过程中的能量损失考虑了氘核与各种带电粒子的库仑散射过程,其能量损失率采用快速带电粒子的慢化理论来计算;氘与背景等离子体中的原子核发生的核反应过程,考虑了非平衡状态下束靶机制的D(t,n)~4He反应和热平衡状态下的D(t.n)~4He反应。在暂未考虑核散射的情况下,计算结果表明,当等离子体温度在7.5KeV～20KeV范围内变化时,氘核的非平衡弛豫过程对热平衡状态下D(t,n)~4He反应率参数的修正因子大致在1.0062～1.0943范围内变动,且温度越高,修正因子越小。计算还表明,当温度一定时,修正因子随等离子体中粒子的数密度变化不明显。

The Effect of Non-equilibrium Relaxation Process of High-speed Nucleus in High Temperature Thermal Equilibrium Plasma on Fusion Reaction Rate Parameter

When high-speed nucleus comes into high temperature thermal equilibrium plasma,there exists a non-equilibrium relaxation process before the incident nucleus reaches athermal equilibrium state with plasma if kinetic energy is far greater than the average ki-netic energy of charged particles in background plasma. In the relaxation process, the ki-netic energy of incident nucleus will be lost individually because of its interaction withbackground plasma. In this paper, we take high speed Tritium of 3MeV energy incidentinto high temperature LiD Plasma as an example, The reaction rate parameter of D(t,n)~4 He reaction in consideration of the non-equilibrium relaxation process of Tritium inthe plasma is calculated. In the calculation, the energy losses of Tritium in plasma,caused by Coulomb Scattering Processes of electrons and variousions is considered, andthe fast-ion unified slowing down theory in plasma proposed by C. K. Choi et al. is usedto calculate the energy loss rate of Tritium. Both the D(t,n)~4 He reaction of beam-targetmechanism in non-equilibrium state and the D(t,n)~4 He reaction in thermal equilibriumstate are considered. Neglecting nuclear scattering and the interference between nuclearscattering and coulomb scattering, the calculated results show that, when the tempera-ture of plasma varies in the range of 7.5KeV~20KeV, the correction factor to reactionrate parameter of D(t,n)~4He in thermal equilibrium state caused by the non-equilibriumrelaxation process of Tritium in Plasma is in the range of 1.0062~1.0943, and the high-er the temperature of plasma is, the smaller the correction factor is. The results alsoshow that, when the temperature of plasma is fixed, the correction factor slightly in-creases as the particle number density of plasma increases, but the change is not promi-nent.