Anomalous momentum transport due to drift-waves in tokamaks

TL;DRAbstract

Transport coefficients for both toroidal and poloidal momentum transport have been derived for the Weiland model. The turbulent drive also gives source terms due to Geodesic Acoustic Modes (GAM’s). A rather complete model has been obtained for the shift in the eigenfunction due to flowshear. The reactive closure of the model enhances diffusivities and source terms associated with temperature perturbations. Momentum pinches are obtained for both poloidal and toroidal flows. The pinch in the toroidal flow is, however, usually rather weak, making a model with only diagonal element reasonable. Nonlinear feedback between flows, flowshear, shift of eigenfunction and turbulence level makes simulations sensitive and it frequently becomes necessary to freeze one or more variables. Introduction The interest in momentum transport has recently increased strongly. This is mainly because of the need to understand the formation of internal transport barriers. While the poloidal momentum transport has

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