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(TH/P1-19) Comprehensive Gyrokinetic Simulation of Tokamak Turbulence at Finite Relative Gyroradius

R. E. Waltz1), J. Candy1), M.N. Rosenbluth1)
1) General Atomics, San Diego, USA

Abstract.  A continuum gyrokinetic code GYRO has been developed to comprehensively simulate turbulent transport in actual experimental profiles and allow direct quantitative comparisons to the experimental transport flows. GYRO not only treats ion temperature gradient (ITG) mode turbulence, but also trapped and passing electrons with collisions and finite beta, with real geometry. Importantly the code operates at finite relative gyroradius ( $ \rho^{\ast}$) so as to treat the profile shear stabilization effects which break gyroBohm scaling. The code operates in a cyclic flux tube limit which allows only gyroBohm scaling and a noncylic radial annulus with physical profile variation. The later requires an adaptive source to maintain equilibrium profiles. Simple ITG simulations demonstrate the broken gyroBohm scaling paradigm of Garbet and Waltz [Phy. Plasmas 3, 1898 (1996)]. Since broken gyroBohm scaling depends on rotational velocity shear rates competing with actual mode growth rates, direct comprehensive simulations of the DIII-D $ \rho^{\ast}$ L-mode experiments are presented as a quantitative test of gyrokinetics and the paradigm. *Work supported by U.S. DOE under Grant No. DE-FG03-95ER54309.

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IAEA 2003