Effect of Triangularity on Ion-Temperature-Gradient-Driven Turbulence

TitleEffect of Triangularity on Ion-Temperature-Gradient-Driven Turbulence
Publication TypeJournal Article
Year of Publication2022
AuthorsJ.M. Duff, B.J. Faber, C.C. Hegna, M.J. Pueschel, P.W. Terry
JournalPhysics of Plasmas
Volume29
Issue1
Pagination012303
Abstract

The linear and nonlinear properties of ion-temperature-gradient-driven (ITG) turbulence with adiabatic electrons are modeled for axisymmetric configurations for a broad range of triangularities δ, both negative and positive. Peak linear growth rates decrease with negative δ but increase and shift toward a finite radial wavenumber kx with positive δ. The growth-rate spectrum broadens as a function of kx with negative δ and significantly narrows with positive δ. The effect of triangularity on linear instability properties can be explained through its impact on magnetic polarization and curvature. Nonlinear heat flux is weakly dependent on triangularity for |δ| ≤ 0.5, decreasing significantly with extreme δ, regardless of sign. Zonal modes play an important role in nonlinear saturation in the configurations studied, and artificially suppressing zonal modes increased nonlinear heat flux by a factor of about four for negative δ, increasing with positive δ by almost a factor of 20. Proxies for zonal-flow damping and drive suggest that zonal flows are enhanced with increasing positive δ.

DOI10.1063/5.0065585
Division

FP

Department

PMT

PIDff16bec0f4031a3afbe84670a6a78059
Alternate TitlePhys. Plasmas
LabelOA
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