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Miki, Kazuhiro; Idomura, Yasuhiro
no journal, ,
Understanding of the energetic particles physics is of great interest in the future burning plasmas. Particularly, particle loss in the presence of EGAM may be critical for ITER. We here introduce energetic particles in a full-f gyrokinetic code (GT5D). (1) We find linear dynamics of the EGAM driven by bump-on-tail particle distributions. We examine flat-q, homogeneous, axisymmetric, electrostatic gyrokinetic simulations. We note that a sufficient resolution on the parallel velocity space is essential to reproduce the EGAM excitation. Above a certain level of the beam intensity, an oscillatory mode grows with about a half of the standard GAM. The observed frequencies are consistent with the eigenmode analyses derived from the perturbed gyrokinetic equations. The theoretical analyses also indicate a bifurcation of the excited modes depending on q-value. An estimation of the finite-orbit-width effects leads us to the reduction of the growth rate. (2) We find linear dynamics of the EGAM driven by slowing-down distributions. We examine the axisymmetric gyrokinetic simulations with DIII-D-like parameters. The observed growth rates and frequencies are consistent with results of other hybrid code.
Maeyama, Shinya; Watanabe, Tomohiko*; Idomura, Yasuhiro; Nakata, Motoki; Yagi, Masatoshi; Miyato, Naoaki; Nunami, Masanori*; Ishizawa, Akihiro*
no journal, ,
no abstracts in English
Nuga, Hideo; Matsuyama, Akinobu; Yagi, Masatoshi; Fukuyama, Atsushi*
no journal, ,
no abstracts in English
Matsuyama, Akinobu; Aiba, Nobuyuki; Yagi, Masatoshi
no journal, ,
no abstracts in English
Miyato, Naoaki
no journal, ,
We perform ion temperature gradient (ITG) driven turbulence simulation in a tokamak plasma with a transient source in a density equation and a transient sink in a ion temperature equation which are localized in the poloidal plane. The source and sink are given after the ITG turbulence saturates. Parameters used in the simulation are similar to those used in the reduced magnetohydrodynamic (RMHD) simulation where a non-local plasma response was observed after the density source was terminated.
Hayashi, Nobuhiko
no journal, ,
no abstracts in English
Idomura, Yasuhiro
no journal, ,
In this talk, main results from the 3rd cycle IFERC-CSC project GT5DISO are reviewed. Full-f gyrokinetic simulations of ion temperature gradient driven turbulence are performed for hydrogen and deuterium plasmas with various normalized machine size and heating power, and hydrogen isotope effects on the confinement property of fusion plasmas. An experimental confinement scaling is recovered with respect to a hydrogen isotope effect through the normalized machine size, while an influence from the ion mass is not clear. This result suggests that simulations including electron turbulence are needed to fully explain the hydrogen isotope effects.