Title: Verification of GENE and GYRO with L-mode and I-mode plasmas in Alcator C-Mod

Abstract

Verification comparisons are carried out for L-mode and I-mode plasma conditions in Alcator C-Mod. We compare linear and nonlinear ion-scale calculations by the gyrokinetic codes GENE and GYRO to each other and to the experimental power balance analysis. The two gyrokinetic codes' linear growth rates and real frequencies are in good agreement throughout all the ion temperature gradient mode branches and most of the trapped electron mode branches of the kyρs spectra at r/a = 0.65, 0.7, and 0.8. The shapes of the toroidal mode spectra of heat fluxes in nonlinear simulations are very similar for kyρs ≤ 0.5, but in most cases GENE has a relatively higher heat flux than GYRO at higher mode numbers. The ratio of ion to electron heat flux is similar in the two codes' simulations, but the heat fluxes themselves do not agree in almost all cases. In the I-mode regime, GENE's heat fluxes are ~3 times those from GYRO, and they are ~60%–100% higher than GYRO in the L-mode conditions. The GYRO under-prediction of Qe is much reduced in GENE's L-mode simulations, and it is eliminated in the I-mode simulations. This largely improved agreement with the experimental electron heat flux is offset, however,more » by the large overshoot of GENE's ion heat fluxes, which are 2–3 times the experimental level, and its electron heat flux overshoot at r/a = 0.80 in the I-mode. Rotation effects can explain part of the difference between the two codes' predictions, but very significant differences remain in simulations without any rotation effects.« less

Authors:

Mikkelsen, D. R.  ^[1];

• Search DOE PAGES for author "Mikkelsen, D. R."
• Search DOE PAGES for ORCID "0000-0003-0865-3703"

Howard, N. T. ^[2]; White, A. E. ^[2]; Creely, A. J.  ^[2]

• Search DOE PAGES for author "Creely, A. J."
• Search DOE PAGES for ORCID "0000-0002-4464-150X"

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+ Show Author Affiliations

1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
2. MIT Plasma Science and Fusion Center, Cambridge, MA (United States)

Publication Date:

Wed Apr 25 00:00:00 EDT 2018

Research Org.:

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); MIT Plasma Science and Fusion Center, Cambridge, MA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES); US Air Force Office of Scientific Research (AFOSR)

OSTI Identifier:

1437592

Alternate Identifier(s):

OSTI ID: 1434559; OSTI ID: 1545790

Grant/Contract Number:  

AC02-09CH11466; AC02-05CH11231; SC0006419; SC0017381; ACO2-09CH11466; FC02-­99ER54512

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 25; Journal Issue: 4; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; eddies; plasma confinement; programming languages; tokamaks; plasma instabilities; fluid flows; thermodynamic processes; Coriolis effects; electrostatics