Global Gyrokinetic Simulation of Tokamak Edge Pedestal Instabilities

Abstract

Global electromagnetic gyrokinetic simulations show the existence of near threshold conditions for both a high-$n$ kinetic ballooning mode (KBM) and an intermediate-$n$ kinetic version of peeling-ballooning mode (KPBM) in the edge pedestal of two DIII-D H-mode discharges. When the magnetic shear is reduced in a narrow region of steep pressure gradient, the KPBM is significantly stabilized, while the KBM is weakly destabilized and hence becomes the most-unstable mode. Collisions decrease the KBM's critical $\beta$ and increase the growth rate.

4 pages, 6 figures

References in corpus (1)

• Kinetic instabilities that limit β in the edge of a tokamak plasma: a picture of an H-mode pedestal

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