(TH/P2-10) Evolution of Anomalous Transport in Shear Flow of Toroidal Devices

V.S. Mikhailenko1), N.A. Azarenkov1), V.V. Mikhailenko1), V.V. Chechkin2), L.I. Grigor'eva2), K.N. Stepanov2), E. L Sorokovoy2), Ye.D. Volkov2)
1) Karazin Kharkov National University
2) National Science Center ``KIPT", Kharkov, Ukraine

Abstract.  The experimentally determined velocity shear in Uragan-3M (U-3M) torsatron in (L-H) - like transition is up to ten times greater than the drift wave frequency. The temporal evolution of the drift and Alfvén turbulence and the resulted anomalous transport are considered under the conditions of modest (flow shear parameter ν0 is of the order of the instabilities growth rate) and strong flow shear (flow shear parameter ν0 is greater than the drift frequency) on the grounds of the non-modal approach. The studies of the dynamics of packets of nonmodal drift waves, eta-i modes, Alfvén waves have shown that the wave packets are stagnated or reflected by the shear flow. The components of the group velocity along the flow shear rapidly vanish with time. The calculated anomalous ion transport displays rapid decreasing with time. The comparative analysis of the linear non-modal effects and nonlinear turbulent effects, such as the effect of the enhanced by flow shear nonlinear decorrelation, on the instabilities evolution and saturation is performed. The renormalized kinetic theory of drift and drift-cyclotron instabilities of a plasma with a transverse inhomogeneous shear flow, which accounts for the turbulent scattering of ions across the shear flow and the enhanced scattering of ions along the shear flow, is developed. The saturation level of the shear-flow-modified drift turbulence and the reduced by the shear flow anomalous fluxes of ions and electrons are determined.

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