T.-H.Watanabe, H.Sugama, and M.


Nunami Isotope Effects on Zonal Flows and Turbulence in Helical Configurations with Equilibrium-Scale Radial Electric Fields

Date of publication:

Nov. 2010

Key words:

22 IAEA Fusion Energy Conference, THC/6-1


Isotope effects on zonal flow response and the ion temperature gradient (ITG) instability in magneticallyconfined plasma with helical configurations are investigated by gyrokinetic simulations. Poloidally global simulations of the collisionless zonal flow damping manifest enhancement of the residual amplitude by the equilibriumscale (uniform and constant) radial electric field (Er0), and show agreement with the zonal flow response kernel analytically derived from the theory for helical plasmas with multiple-helicity confinement field components. The higher zonal flow response is found with heavier ion mass for the same ion temperature (Ti) and Er0, because effects of the radial electric field are introduced in terms of the poloidal Mach number (Mp), while the ITG mode frequency is Doppler-shifted. Accordingly, the isotopic dependence of the zonal flow response through Er0 leads to the mass (or Mp) dependence of the turbulent transport.

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