211 citations · 768 across the 32 of their papers we have counts for
32 papers
MGKDB: An IMAS-aligned multicode gyrokinetic simulation database for reproducible fusion turbulence modeling and data-driven analysis
Craig Michoski, David R. Hatch, Dongyang Kuang +14
Expensive fusion simulations are commonly preserved in code-specific formats that limit discovery, comparison, and reuse. We present the Multiscale GyroKinetic DataBase (MGKDB), an…
Characterizing Flux-Surface Shapes in Tokamaks and Quasi-Symmetric Stellarators
M. J. Gerard, M. J. Pueschel, S. Stewart +2
Modern stellarator designs routinely attain high levels of magnetic-field quasi-symmetry through flux-surface shaping. Here, we examine different methods for characterizing stellar…
Characterization of reduced-order turbulence models in the L-mode pedestal-forming region in JET
G. Snoep, C. Bourdelle, J. Citrin +7
Linear instability characterization of seven JET discharges just prior to the L-H transition is performed at with the gyrokinetic GENE code. Th…
Suppressing Trapped-Electron-Mode-Driven Turbulence via Optimization of Three-Dimensional Shaping
J. M. Duff, B. J. Faber, C. C. Hegna +2
Turbulent transport driven by trapped electron modes (TEMs) is believed to drive significant heat and particle transport in quasihelically symmetric stellarators. Two three-dimensi…
Flexible Stellarator Physics Facility
F. I. Parra, S. -G. Baek, M. Churchill +21
We propose to build a Flexible Stellarator Physics Facility to explore promising regions of the vast parameter space of disruption-free stellarator solutions for Fusion Pilot Plant…
Gyrokinetic investigation of toroidal Alfven eigenmode (TAE) turbulence
Ajay C. J., Ben McMillan, Arkaprava Bokshi +3
Toroidal Alfvén eigenmodes (TAEs) can transport fusion-born energetic particles out of the plasma volume, thereby decreasing plasma self-heating efficiency and possibly damaging re…
On the effect of flux-surface shaping on trapped-electron modes in quasi-helically symmetric stellarators
M. J. Gerard, M. J. Pueschel, B. Geiger +5
Using a novel optimization procedure it has been shown that the Helically Symmetric eXperiment (HSX) stellarator can be optimized for reduced trapped-electron-mode (TEM) instabilit…
Influence of collisions on trapped-electron modes in tokamaks and low-shear stellarators
M. C. L. Morren, J. H. E. Proll, J. van Dijk +1
The influence of collisions on the growth rate of trapped-electron modes (TEMs) in core plasmas is assessed through both analytical linear gyrokinetics and linear gyrokinetic simul…
Three-Dimensional Shear-Flow Instability Saturation via Stable Modes
B. Tripathi, P. W. Terry, A. E. Fraser +2
Turbulence in three dimensions (D) supports vortex stretching that has long been known to accomplish energy transfer to small scales. Moreover, net energy transfer from large-sc…
Global Linear and Nonlinear Gyrokinetic Simulations of Tearing Modes
T. Jitsuk, A. Di Siena, M. J. Pueschel +4
To better understand the interaction of global tearing modes and microturbulence in the Madison Symmetric Torus (MST) reversed-field pinch (RFP), the global gyrokinetic code \texts…
Nonlinear mode coupling and energetics of driven magnetized shear-flow turbulence
B. Tripathi, A. E. Fraser, P. W. Terry +3
To comprehensively understand saturation of two-dimensional (D) magnetized Kelvin-Helmholtz-instability-driven turbulence, energy transfer analysis is extended from the traditio…
Near-cancellation of up- and down-gradient momentum transport in forced magnetized shear-flow turbulence
B. Tripathi, A. E. Fraser, P. W. Terry +2
Visco-resistive magnetohydrodynamic turbulence, driven by a two-dimensional unstable shear layer that is maintained by an imposed body force, is examined by decomposing it into dis…
Microtearing turbulence saturation via electron temperature flattening at low-order rational surfaces
Ajay C. J., Ben McMillan, M. J. Pueschel
Microtearing instability is one of the major sources of turbulent transport in high- tokamaks. These modes lead to very localized transport at low-order rational magnetic field…
Mechanism for Sequestering Magnetic Energy at Large Scales in Shear-Flow Turbulence
B. Tripathi, A. E. Fraser, P. W. Terry +2
Straining of magnetic fields by large-scale shear flow, generally assumed to lead to intensification and generation of small scales, is re-examined in light of the persistent obser…
Reduced models for ETG transport in the pedestal
David R. Hatch, Craig Michoski, Dongyang Kuang +10
This paper reports on the development of reduced models for electron temperature gradient (ETG) driven transport in the pedestal. Model development is enabled by a set of 61 nonlin…
Anisotropic cosmic-ray diffusion in isotropic Kolmogorov turbulence
P. Reichherzer, J. Becker Tjus, E. G. Zweibel +2
Understanding the time scales for diffusive processes and their degree of anisotropy is essential for modelling cosmic-ray transport in turbulent magnetic fields. We show that the…
Implications of turbulence-dependent diffusion on cosmic-ray spectra
J. Dörner, P. Reichherzer, L. Merten +4
The propagation of cosmic rays can be described as a diffusive motion in most galactic environments. High-energy gamma-rays measured by Fermi have allowed inference of a gradient i…
Regimes of cosmic-ray diffusion in Galactic turbulence
P. Reichherzer, L. Merten, J. Dörner +3
Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This proc…
Comparison of local and global gyrokinetic calculations of collisionless zonal flow damping in quasi-symmetric stellarators
J. Smoniewski, E. Sánchez, I. Calvo +2
The linear collisionless damping of zonal flows is calculated for quasi-symmetric stellarator equilibria in flux-tube, flux-surface, and full-volume geometry. Equilibria are studie…
Importance of theory, computation and predictive modeling in the US magnetic fusion energy strategic plan
Fatima Ebrahimi, Gary Staebler, Paul Bonoli +5
Based on the community input at the National Academy of Sciences (NAS) Madison and Austin workshops in July and December 2017, respectively, this whitepaper was prepared and submit…
The impact of magnetic fields on momentum transport and saturation of shear-flow instability by stable modes
A. E. Fraser, P. W. Terry, E. G. Zweibel +2
The Kelvin-Helmholtz (KH) instability of a shear layer with an initially-uniform magnetic field in the direction of flow is studied in the framework of 2D incompressible magnetohyd…
Microtearing modes as the source of magnetic fluctuations in the JET pedestal
D. R. Hatch, M. Kotschenreuther, S. M. Mahajan +15
We report on a detailed study of magnetic fluctuations in the JET pedestal, employing basic theoretical considerations, gyrokinetic simulations, and experimental fluctuation data,…
Suppression of turbulence by trapped electrons in optimised stellarators
J. H. E. Proll, P. Xanthopoulos, P. Helander +5
In fusion devices, the geometry of the confining magnetic field has a significant impact on the instabilities that drive turbulent heat loss. This is especially true of stellarator…
Turbulence-Level Dependence of Cosmic-Ray Parallel Diffusion
P. Reichherzer, J. Becker Tjus, E. G. Zweibel +2
Understanding the transport of energetic cosmic rays belongs to the most challenging topics in astrophysics. Diffusion due to scattering by electromagnetic fluctuations is a key pr…