May 8-10

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Abstracts

Author: Scott E. Parker
Requested Type: Poster
Submitted: 2023-03-29 15:59:31

Co-authors: Q. Cai, Y. Chen, C. Haubrich, S. Tiras, G. Merlo

Contact Info:
University of Colorado
2000 Colorado Ave.
Boulder, CO   80309
USA

Abstract Text:
We have brought together a variety of widely used tools to study collisional and turbulent transport in toroidal fusion plasmas. The goal is the understanding of experimental trends using state-of-the-art theory tools with an easy to use, fast time to solution, and completely open-source environment. We use the GENE gyrokinetic code for detailed linear calculations and electron-scale nonlinear simulations. The local approximation is valid for nonlinear electron-scale turbulence. Linear GENE calculations provide ion-scale and electron-scale eigenvalue and eigenmode information for detailed quasilinear flux estimates. In good confinement regimes, it is reasonable to assume that the turbulent fluctuations are made up of a superposition of linear eigenmodes, so that the quasilinear expression for the fluxes is valid. What is more uncertain is the turbulent saturation level. Rather than choosing an ad-hoc, data-driven, or empirical saturation rule, we quicky “scan” sensitivity to the saturation rule by comparing three theory-based models capturing what is currently used in the community. In addition, we compare our three saturation rules to TGLF. For ion-scale nonlinear simulation we employ the global GEM gyrokinetic code which obtains nonlinear steady state with modest HPC computer resources. Finally, we utilize the very fast NEO code for comparison with neoclassical transport levels. All these codes are in the public domain and the University of Colorado gyrokinetic workflow (CUGK) is bundled as Python scripts and is available on GitHub (individual component codes will need to be accessed independently). CUGK is easy to use and further develop. We have utilized CUGK to examine the role of Carbon in the inter-ELM buildup of H-mode profiles on DIII-D, as well as modeling transport of D, T, He and W in ITER high performance profiles.

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