NachhaltigAngewandte Naturwissenschaften und Wirtschaftsingenieurwesen
S. Liu, S. Dai, C. Sang, J. Sun, Thomas Stirner, D. Wang
Molecular dynamics simulation of the formation, growth and bursting of bubbles in tungsten exposed to high fluxes of low energy deuterium
Journal of Nuclear Materials - PLASMA-SURFACE INTERACTIONS 21 — Proceedings of the 21st International Conference on Plasma-Surface Interactions in Controlled Fusion Devices Kanazawa, Japan, May 26-30, 2014, vol. 463, no. August, pp. 363-366
Molecular dynamics simulations are carried out to investigate the formation, growth and bursting of bubbles in tungsten exposed to the irradiation of an extremely high deuterium flux. It is found that the bubbles form in the region near the location of the implanted ion distribution peaks, and that the effect of the substrate temperature on the bubble formation depth is negligible; it is also found that the percentage of deuterium that is found in D2 molecules increases as the bubble grows, and that the evolution of the bubble’s internal pressure is strongly associated with the properties of its surrounding structure. The simulations display the development of a dome-shaped structure at the tungsten surface during the bubble growth. The merging of two deuterium bubbles is also observed. The present simulations also show that the bubble bursts by generating a partially opened lid, which has already been observed in previous independent experiments.
Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
J. Sun, C. Sang, Thomas Stirner
Characteristics of plasma immersion ion implantation with a nanosecond rise-time pulse: particle-in-cell simulations
Journal of Physics D: Applied Physics, vol. 43
Processes of plasma immersion ion implantation are analyszed numerically using a one-dimension-in-space and three-dimension-in-velocity particle-in-cell plus Monte Carlo collision (1D3V PIC–MCC) model. The behaviour of ions and electrons between the processed target and the source plasma is simulated after a nanosecond rise-time voltage pulse is applied to the target. The simulation results show that electron–neutral ionization collisions play a significant role in determining the magnitudes of the ion and electron densities when the pulse rise time is very short, and that the plasma density can be enhanced many times. The physical mechanism for this phenomenon is explained in terms of the formation of a reverse electric field inside the plasma chamber.