مجله علوم و فنون هسته‌ای (Sep 2021)

Simulation of collision of dust nanoparticles with graphite wall using LAMMPS code

  • M. Bakhtiyari Ramezani,
  • M. Abdollahi Dargah,
  • N. Abdollahi Ghahi

DOI
https://doi.org/10.24200/nst.2021.1294
Journal volume & issue
Vol. 42, no. 3
pp. 37 – 43

Abstract

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In the present work, we have simulated the collision of dust nanoparticles with graphite wall using LAMMPS code, based on the molecular dynamics method. Dust particles have different shapes and sizes depending on their production mechanism in Tokamaks. In this work, two types of dust grains have been considered: a spherical tungsten nanoparticle and a graphite nanoparticle with an oblate geometry that collides with a graphite wall. In the fusion device, ions, hydrogen atoms, and molecules collide with the dust grain and create stochastic torques, leading to minor variations in the angular momentum of the grain. Therefore, in the simulations, the dust rotation around its symmetry axis has also been considered in addition to the transfer velocity. For such nanoparticles, the threshold speed of nanoparticles that leads to surface damage has been estimated. The results show that, unlike tungsten nanoparticles, graphite grains do not play a significant role in the degradation of the graphite surfaces. Still, due to the speed of the collision, they may either stick to the surface or be damaged and return to the environment.

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