title: Fast ion induced shearing of 2D Alfvén eigenmodes measured by electron cyclotron emission imaging.
abstract: Two-dimensional images of electron temperature perturbations are obtained with electron cyclotron emission imaging (ECEI) on the DIII-D tokamak and compared to Alfvén eigenmode structures obtained by numerical modeling using both ideal MHD and hybrid MHD-gyrofluid codes. While many features of the observations are found to be in excellent agreement with simulations using an ideal MHD code (NOVA), other characteristics distinctly reveal the influence of fast ions on the mode structures. These features are found to be well described by the nonperturbative hybrid MHD-gyrofluid model TAEFL.
authors.affiliation: University of California, Davis, 95616, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Tobias
authors.forename: I G J
authors.initials: IG
authors.lastname: Classen
authors.forename: C W
authors.initials: CW
authors.lastname: Domier
authors.forename: W W
authors.initials: WW
authors.lastname: Heidbrink
authors.forename: N C
authors.initials: NC
authors.lastname: Luhmann
authors.forename: R
authors.initials: R
authors.lastname: Nazikian
authors.forename: H K
authors.initials: HK
authors.lastname: Park
authors.forename: D A
authors.initials: DA
authors.lastname: Spong
authors.forename: M A
authors.initials: MA
authors.lastname: Van Zeeland