title: Nonlinear stabilization of tokamak microturbulence by fast ions.
abstract: Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting significantly the thermal pressure electromagnetic stabilization. Based on nonlinear gyrokinetic simulations investigating a set of ion heat transport experiments on the JET tokamak, described by Mantica et al. [Phys. Rev. Lett. 107, 135004 (2011)], this result explains the experimentally observed ion heat flux and stiffness reduction. These findings are expected to improve the extrapolation of advanced tokamak scenarios to reactor relevant regimes.
authors.affiliation: FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands and CEA, IRFM, F-13108 Saint Paul Lez Durance, France.
authors.forename: J
authors.initials: J
authors.lastname: Citrin
authors.forename: F
authors.initials: F
authors.lastname: Jenko
authors.forename: P
authors.initials: P
authors.lastname: Mantica
authors.forename: D
authors.initials: D
authors.lastname: Told
authors.forename: C
authors.initials: C
authors.lastname: Bourdelle
authors.forename: J
authors.initials: J
authors.lastname: Garcia
authors.forename: J W
authors.initials: JW
authors.lastname: Haverkort
authors.forename: G M D
authors.initials: GM
authors.lastname: Hogeweij
authors.forename: T
authors.initials: T
authors.lastname: Johnson
authors.forename: M J
authors.initials: MJ
authors.lastname: Pueschel