I1-S3 · Theory of the Anomalous Transport ReductionKim, Eun-jin1) Abstract There has been mounting evidence from laboratory and computer experiments that the reduction in turbulent transport by shearing by mean BxE flows and zonal flows is critical to the formation of transport barrier (e.g. the L-H transition and the formation of internal transport barrier). In particular, the recent theoretical study has indicated that zonal flows play an important role in regulating turbulence before the L-H transition until the shearing by mean flows becomes dominant due to the steepening of the mean pressure gradient near the transition, keeping the plasmas in the H-mode after the transition. Therefore, the medelling of the formation of transport barrier requires a quantitative prediction as to how much flux is reduced by both mean and zonal flows. Here, we consider a few simple turbulence models to study the scaling of the transport with (mean or RMS) shearing rate and then to examine the model dependence of such scalings.
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