Flow Shear Suppression of Pedestal Turbulence--A First Principles Theoretical Framework

Abstract

A combined analytic and computational gyrokinetic approach is developed to address the question of the scaling of pedestal turbulent transport with arbitrary levels of $E\times B$ shear. Due to strong gradients and shaping in the pedestal, the instabilities of interest are not curvature-driven like the core instabilities. By extensive numerical (gyrokinetic) simulations, it is demonstrated that pedestal modes respond to shear suppression very much like the predictions of a basic analytic decorrelation theory. The quantitative agreement between the two provides us with a new dependable, first principles (physics based) theoretical framework to predict the efficacy of shear suppression in burning plasmas that lie in a low-shear regime not accessed by present experiments.

References in corpus (4)

• Kinetic instabilities that limit β in the edge of a tokamak plasma: a picture of an H-mode pedestal
• Turbulent transport in tokamak plasmas with rotational shear
• Local and global Fokker-Planck neoclassical calculations showing flow and bootstrap current modification in a pedestal
• A New Paradigm for Turbulent Transport Across a Steep Gradient in Toroidal Plasmas

Cited by in corpus (5)

• Gyrokinetic analysis and simulation of pedestals, to identify the culprits for energy losses using fingerprints
• Direct Gyrokinetic Comparison of Pedestal Transport in JET with Carbon and ITER-Like Walls
• Broadening of the Divertor Heat Flux Profile in High Confinement Tokamak Fusion Plasmas with Edge Pedestals Limited by Turbulence in DIII-D
• Suppression of temperature-gradient-driven turbulence by sheared flows in fusion plasmas
• Transition from weak to strong turbulence in magnetized plasmas