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Aiba, Nobuyuki; Furukawa, Masaru*; Hirota, Makoto; Tokuda, Shinji
no journal, ,
no abstracts in English
B flowMiyato, Naoaki; Scott, B. D.*; Strintzi, D.*; Tokuda, Shinji
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We derive a modified guiding-centre fundamental 1-form with strong EB flow whose symplectic part does not include the flow term or time dependence. Since the symplectic part of the derived 1-form is the same as the standard one without the strong flow formally, it yields the standard Lagrange and Poisson brackets. Therefore the guiding-centre Hamilton equations keep their general form even when temporal evolution of the EB flow is allowed. On the other hand, the guiding-centre Hamiltonian is more complicated than the conventional one. However it is possible to simplify the Hamiltonian in well localised transport barrier regions like the tokamak H-mode edge and internal transport barriers in reversed shear tokamaks. The guiding-centre Vlasov and Poisson equations are derived from the variational principle. The conserved energy of the system is obtained by the Noether's method.
Honda, Mitsuru; Takizuka, Tomonori; Fukuyama, Atsushi*; Takenaga, Hidenobu; Yoshida, Maiko; Ozeki, Takahisa
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We have studied the characteristic of the turbulent particle transport model in the TASK/TX code and the effect of core neutrals on the formation of the density profile. The turbulent particle transport in TASK/TX is described through the momentum exchange between electrons and ions. Although this model has successfully induced the turbulent transport, the effective particle diffusivity has been different from the input one. We have analytically clarified that the present model inherently causes the outward pinch in addition to the turbulent diffusion and we have numerically confirmed thereof. The newly-developed model can annihilate the inherit outward pinch to produce a pure turbulent diffusion. An anomlaous inward pinch seems to exist if the density peaking is observed. However, we have confirmed from numerical simulations that it is possible to form the density peaking without any anomalous inward pinch when thermal neutrals are supplied to the core to some extent.
Hirota, Makoto; Tokuda, Shinji
no journal, ,
In various theories such as stability, wave-mean field interaction and weak turbulence, the wave action (or wave quantum) is worth studying since it is conserved with good accuracy in weakly nonlinear phenomena. In this work, without invoking the short wavelength limit, we have developed a technique for evaluating the wave action not only for each single eigenmode, but also for a continuum mode. The adiabatic invariance of the wave action can be discussed for both eigenmodes and continuum modes. It is decisive in determining whether resonant coupling between an eigenmode and a continuum mode leads to either exponential growth or continuum damping (Landau damping).
Shiraishi, Junya; Tokuda, Shinji; Aiba, Nobuyuki
no journal, ,
no abstracts in English
Ishii, Yasutomo; Smolyakov, A. I.*
no journal, ,
no abstracts in English
Tokuda, Shinji; Kagei, Yasuhiro*
no journal, ,
Recently, the authors have proposed, for MHD stability analysis, a numerical matching scheme that introduces a thin inner layer with finite width. In this work we discuss the analytical procedure that solves the inner layer equation by perturbation methods and determines the eigenfunctions and eigenvalues; in the analysis the smallness of the width compared with the plasma radius is exploited. The first order equation gives us the dispersion relation that determines the eigenvalues; the dispersion relation accords with that in the asymptotic matching method. In order to solve the next order equation, we propose the Hamilton-Lie perturbation method with the conjugate variables.
Jolliet, S.; McMillan, B. F.*; Bottino, A.*; Angelino, P.*; Lapillonne, X.*; Vernay, T.*; Idomura, Yasuhiro; Villard, L.*
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Idomura, Yasuhiro
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Lesur, M.*; Idomura, Yasuhiro; Garbet, X.*
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