Gyrokinetic GENE simulations of DIII-D near-edge L-mode plasmas

T. F. Neiser, F. Jenko, T. A. Carter, L. Schmitz, D. Told, G. Merlo, A. Banõn Navarro, P. C. Crandall, G. R. McKee, Z. Yan

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

We present gyrokinetic simulations with the GENE code addressing the near-edge region of an L-mode plasma in the DIII-D tokamak. At radial position ρ = 0.80, simulations with the ion temperature gradient (ITG) increased by 40% above the nominal value give electron and ion heat fluxes that are in simultaneous agreement with the experiment. This gradient increase is consistent with the combined statistical and systematic uncertainty σ of the charge exchange recombination spectroscopy measurements at the 1.6σ level. Multiscale simulations are carried out with a realistic mass ratio and geometry for the first time in the near-edge. These multiscale simulations suggest that the highly unstable ion temperature gradient (ITG) modes of the flux-matched ion-scale simulations suppress electron-scale transport, such that ion-scale simulations are sufficient at this location. At radial position ρ = 0.90, nonlinear simulations show a hybrid state of ITG and trapped electron modes, which was not expected from linear simulations. The nonlinear simulations reproduce the total experimental heat flux with the inclusion of E × B shear effects and an increase in the electron temperature gradient by ∼23%. This gradient increase is compatible with the combined statistical and systematic uncertainty of the Thomson scattering data at the 1.3σ level. These results are consistent with previous findings that gyrokinetic simulations are able to reproduce the experimental heat fluxes by varying input parameters close to their experimental uncertainties, pushing the validation frontier closer to the edge region.

Original languageEnglish
Article number092510
JournalPhysics of Plasmas
Volume26
Issue number9
DOIs
StatePublished - Sep 1 2019
Externally publishedYes

Funding

The authors wish to thank Tobias Gorler, Nathan Howard, Chris Holland, Walter Guttenfelder, Craig Petty, Punit Gohil, Wayne Solomon, Martin Weidl, and Qingjiang Pan for helpful questions and comments. This work was supported by the U.S. Department of Energy (DOE) under Award No. DE-SC0016073. The computational effort was conducted at NERSC, a DOE Office of Science User Facility supported under Contract No. DE-AC02-05CH11231. The experimental work at DIII-D was supported by the U.S. DOE under Contract Nos. DE-FG02-08ER54984 and DE-FC02-04ER54698.

Fingerprint

Dive into the research topics of 'Gyrokinetic GENE simulations of DIII-D near-edge L-mode plasmas'. Together they form a unique fingerprint.

Cite this