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Idomura, Yasuhiro
no journal, ,
Comparisons between flux driven full-f gyrokinetic simulations and gradient driven delta-f gyrokinetic simulations are discussed with respect to i) turbulent momentum transport and ii) plasma size and power scaling of ion temperature gradient driven turbulence. In the former problem, the ambipolar condition including both turbulent and neoclassical transport is essential in estimating momentum transport and resulting plasma rotation profiles. In the latter problem, self-consistent interactions between temperature fluctuations and turbulent transport under a local power balance condition lead to the power degradation of confinement. These mechanisms are unique to full-f simulations and give significant impact on the estimation of plasma confinement performances.
Idomura, Yasuhiro
no journal, ,
Decaying turbulence simulations of ion temperature gradient driven (ITG) turbulence with adiabatic electrons and ion temperature gradient driven trapped electron mode (ITG-TEM) turbulence with kinetic electrons are performed using a full-f gyrokinetic code. Nonlinear critical temperature gradients exceeding linear critical temperature gradients are observed in both simulations, and mechanisms to sustain them are investigated. It is found that unlike zonal flows in the ITG turbulence, the ITG-TEM turbulence produces corrugated electron density profiles, which form radial electric fields with strong shear following a force balance relation.