National Institutes of Natural Science, National Institute for Fusion Science
Department of Helical Plasma Research, Fundamental Physics Simulation Research Division


NINS Prize for Young Scientists

Assistant Professor Atsushi M. Ito won the NINS Prize for Young Scientists.
  • Date: Jun. 15, 2014
  • Title:                                                                  Theoretical Simulation Researches on Plasma-Material Interaction Phenomena

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  • Context:
    The plasma-wall interaction problems, which are caused by the interaction between confined plasma and the surface of the inside wall of vacuum vessel, have been investigated by using numerical simulation approaches. There are many important problems in the PWI phenomena, such as the sputtering on the surfaces, the generation of the impurity from the surface erosion, the re-deposition of the impurities, the retention of the tritium. To represent these PWI problems in atomic scale, the molecular dynamics (MD) simulation was adopted.

    First, the interaction between plasma and the carbon materials which is plasma facing material used as divertor plates were researched. Especially, the mechanism of chemical sputtering was solved by using the MD simulation[1]. Since the tungsten materials becomes the candidate to be used as divertor material in ITER, the simulation researches on the interaction between plasma and tungsten materials were started. As new approaches, the density functional theory (DFT)[2,3] and kinetic Monte-Carlo (KMC) were employed. By using multi-scale simulation approach composed of these simulation methods, the formation mechanism of the tungsten fuzzy nanostructure was solved[4].

    This study is supported by not only plasma and fusion researchers but also material science researches. The collaboration between plasma and fusion science and material science is necessary for the investigation of the PWI problems. We continue to this advance Cross-Disciplinary Study.


[1] A. Ito, K. Ohya, K. Inai, H. Nakamura, Contrib. Plasma Phys. 50 (2010), 464.
[2] A. M. Ito, S. Saito, A. Takayama, H. Nakamura, Jpn. J. Appl. Phys. 52 (2013) 01AL04.
[3] A. M. Ito, Y. Yoshimoto, S. Saito, A. Takayama, H. Nakamura, Phys. Scr. T159 (2014) 014062.
[4] A. M. Ito, A. Takayama, Y. Oda, T. Tamura, R. Kobayashi, T. Hattori, S. Ogata, N. Ohno, S. Kajita, M. Yajima, Y. Noiri, Y. Yoshimoto, S. Saito, S. Takamura and H. Nakamura, "Molecular dynamics research on formation mechanism of tungsten nanostructure induced by helium plasma irradiation", the 21st International Conference on Plasma Surface Interactions in Controlled Fusion Devices(PSI 21), Kanazawa, Japan, May 26-30, 2014. (invitated talk).