Gyrokinetic Simulations of Slab Ion Temperature Gradient Turbulence with Kinetic Electrons

概要

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Ion temperature gradient (ITG) driven turbulence is investigated by means of gyrokinetic simulations which include both kinetic ions and electrons in slab geometry with uniform equilibrium magnetic field. The study confirms that numerical results satisfy the entropy balance equation including both ions and electrons. The entropy variable is transferred from ions to electrons through the perturbation of electrostatic potential, and the transferred fluctuation is diffused by the electron collision dissipation. In the ITG turbulence with kinetic electrons ion heat diffusion is larger than that with adiabatic electrons. The former is close to the latter when the ion mass is comparable to or larger than the hydrogen one. The difference between the transport coefficients does not originate from the suppression of turbulence by zonal flow, but stems from the difference between their spectra. The lowest wavenumber mode dominates the coefficient in the adiabatic electron case, while the transport is caused not only by the the lowest mode but by higher wavenumbers in the kinetic electron cases.