Examination of the Role of Shear Flow on Transport Phase Angles, D. Baver, P.W. Terry, A.S. Ware, P.H. Diamond, and B.A. Carreras, to be presented at 1996 APS Division of Plasma Physics Meeting.
The suppression of anomalous transport by sheared E´B flow occurs both through reduction of fluctuation amplitudes and changes in the phase angle between fluctuations.1 Here we examine the effect of shear flow on transport phase angles in two models, emphasizing how dissipation affects this process and comparing with experiment. First, edge turbulence is studied using a resistive interchange model with passively advected temperature fluctuations. Because temperature fluctuations are subject to stronger dissipation than density fluctuations (through parallel thermal conduction), it is predicted that shear flow can dramatically reduce particle transport while leaving heat transport practically unchanged, a situation observed in the edge of CCT and MST. Second, we examine trapped electron mode turbulence and study how particle transport reductions due to shear flow are modified as the collisionality changes. Trapped electron responses in collisionless and dissipative regimes are also examined in the context of the ion temperature gradient driven ion mixing mode. The behavior of transport fluxes is examined in relation to core transport barriers formed under negative magnetic shear.