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Author(s):
T.-H. Watanabe and H. Sugama
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Title:
Kinetic Simulation of Steady States of Ion Temperature Gradient Driven Turbulence with Weak Collisionality
Date of publication:
Nov. 2003
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Key words:
gyrokinetics, turbulence, transport, computer simulation
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Abstract:
Statistically steady states of the ion temperature gradient driven turbulence with weak collisionality are investigated by means of a kinetic simulation based on the gyrokinetic equations. Even if the collision frequency is much lower than characteristic ones of the turbulence, it is indispensable to realizing a steady state of perturbed distribution function delta f. In a low-collisionality limit, the low-order velocity-space moments of delta f as well as the ion heat transport flux agree with those in the quasisteady state of the collisionless turbulence. A spectral analysis of delta f in the velocity-space clarifies the transfer and dissipation processes of the entropy variable associated with fluctuations, where the phase mixing, the E ¡ß B nonlinearity, and the finite collisionality are taken into account. A power-law scaling predicted by the theoretical analysis is also verified by the simulations in a subrange of the power spectrum which is free from the entropy production and the collisional dissipation.
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