title: High-frequency coherent edge fluctuations in a high-pedestal-pressure quiescent H-mode plasma.
abstract: A set of high frequency coherent (HFC) modes (f=80-250 kHz) is observed with beam emission spectroscopy measurements of density fluctuations in the pedestal of a strongly shaped quiescent H-mode plasma on DIII-D, with characteristics predicted for kinetic ballooning modes (KBM): propagation in the ion-diamagnetic drift direction; a frequency near 0.2-0.3 times the ion-diamagnetic frequency; inferred toroidal mode numbers of n∼10-25; poloidal wave numbers of k(θ)∼0.17-0.4 cm(-1); and high measured decorrelation rates (τ(c)(-1)∼ω(s)∼0.5×10(6) s(-1)). Their appearance correlates with saturation of the pedestal pressure.
authors.affiliation: University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Yan
authors.forename: G R
authors.initials: GR
authors.lastname: McKee
authors.forename: R J
authors.initials: RJ
authors.lastname: Groebner
authors.forename: P B
authors.initials: PB
authors.lastname: Snyder
authors.forename: T H
authors.initials: TH
authors.lastname: Osborne
authors.forename: K H
authors.initials: KH
authors.lastname: Burrell