Molecular Dynamics Simulation Of The Interaction Between Low-energetic Hydrogen And Its Isotopes And Tungsten Surface

Nuclear fusion energy provides a possibility for the sustainable development of human beings. However, in fusion devices, the fusion reaction does not take place in a complete vacuum environment. Thus it will result in intense interaction between the plasma and the facing wall. The interaction will result in damage effects, which shorten the service life of the wall materials, and increase tritium retention rate. In addition, the interaction can produce large amounts of impurities which will cool the plasma and even lead to discharge extinction. Therefore, in fusion devices, it is particularly necessary to study the interactions between plasma and its facing wall materials.In this thesis, molecular dynamics method is used to simulate the interaction mechanism between hydrogen and its isotopes of low energy and the surface of tungsten target. There are several research topics in this thesis, which follows:First, the retention depth distribution and energy deposition distribution of incident hydrogen and its isotopes in the tungsten target with smooth surface are presented. Second, we study the interaction between incident deuterium particles with different incident energies and smooth tungsten target. Third, we investigate the effect of smooth tungsten target surface with different temperatures on the retention distribution and the energy deposition distribution. Fourth, we research the effect of surface roughness of tungsten target on retention rate and the retention depth distribution of incident particles. Finally, we also discuss the effect of hydrogen and its isotopes existing in tungsten target on the incident particles.The results show that hydrogen and its isotopes are reflected mostly and the rest are retained mainly in the surface of tungsten target. The greater the relative mass of incident particles, the greater the retention rate, the faster the energy deposition and the shallower the retention depth. The greater the energy of incident particles, the greater of retention rate, the deeper the retention position, the slower the energy deposition. The temperature of the tungsten target affects deuterium reflection rate, while it has little influence on the depth distribution and the energy deposition distribution of the incident particles. Deuterium particles of low energy bombarding rough tungsten targets shows that the larger the surface roughness, the larger the retention rate, the deeper the retention position. In addition, simulating the interaction between low-energetic deuterium particles and the tungsten target containing certain percentage of deuterium particles reveals the presence of deuterium particles in tungsten target can suppress the entry of incident particles, and the incident particles can entry the shallower region of the tungsten.