title: Stellarator Turbulence: Subdominant Eigenmodes and Quasilinear Modeling.
abstract: Owing to complex geometry, gyrokinetic simulations in stellarator geometry produce large numbers of subdominant unstable and stable, near-orthogonal eigenmodes. Here, results based on the full eigenmode spectrum in stellarator geometry are presented for the first time. In the nonlinear state of a low-magnetic-shear ion-temperature-gradient-driven case, a multitude of these modes are active and imprint the system. Turbulent frequency spectra are broadband as a consequence, in addition to a nonlinear, narrow signature at electron frequencies. It is shown that successful quasilinear, mixing-length transport modeling is possible in stellarators, where it is essential to account for all subdominant unstable modes.
authors.affiliation: University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Pueschel
authors.affiliation: University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Faber
authors.affiliation: FOM Institute DIFFER, 3430 BE Nieuwegein, The Netherlands.|CEA, IRFM, F-13108 Saint Paul Lez Durance, France.
authors.forename: J
authors.initials: J
authors.lastname: Citrin
authors.affiliation: University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: C C
authors.initials: CC
authors.lastname: Hegna
authors.affiliation: University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: P W
authors.initials: PW
authors.lastname: Terry
authors.affiliation: Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Hatch