title: 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 β and increase the growth rate.
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Weigang
authors.initials: W
authors.lastname: Wan
authors.forename: Scott E
authors.initials: SE
authors.lastname: Parker
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yan
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Groebner
authors.forename: Philip B
authors.initials: PB
authors.lastname: Snyder