Edge turbulence and divertor heat flux width simulations of Alcator C-Mod discharges using an electromagnetic two-fluid model

Chen, B.; Xu, X. Q.; Xia, T. Y.; Porkolab, M.; Edlund, E.; LaBombard, B.; Terry, J.; Hughes, J. W.; Mao, S. F.; Ye, M. Y.; Wan, Y. X.

doi:10.1088/1741-4326/aa7d46

Title: Edge turbulence and divertor heat flux width simulations of Alcator C-Mod discharges using an electromagnetic two-fluid model

Journal Article · Wed Aug 09 00:00:00 EDT 2017 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aa7d46· OSTI ID:1566032

Chen, B. ^[1]; Xu, X. Q. ^[2]; Xia, T. Y. ^[3]; Porkolab, M. ^[4]; Edlund, E. ^[4];

^[4];

^[4]; Hughes, J. W. ^[4]; Mao, S. F. ^[5]; Ye, M. Y. ^[5]; Wan, Y. X. ^[5]

Univ. of Science and Technology of China, Hefei (China); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chinese Academy of Sciences (CAS), Hefei (China)
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Univ. of Science and Technology of China, Hefei (China)

The BOUT++ code has been utilized in order to improve the understanding of the role of turbulent modes in controlling edge transport and resulting scaling of the scrape-off layer (SOL) heat flux width. For the C-Mod enhanced D_α (EDA) H-mode discharges, BOUT++ six-field two-fluid nonlinear simulations show a reasonable agree- ment of upstream turbulence and divertor target heat flux behavior: a) The simulated quasi-coherent modes (QCMs) show consistent characteristics of the frequency versus poloidal wave number spectra of the electromagnetic fluctuations when compared with experimental measurements: frequencies are around 60-120 kHz (experiment: about 70-110 kHz), k_θ are around 2.0 cm^₋1 which is similar to the Phase Contrast Imaging data; b) Linear spectrum analysis is consistent with the nonlinear phase relationship cal- culation which indicates the dominance of resistive-ballooning modes and drift-Alfven wave instabilities; c) The SOL heat flux width λ_q vs current I_p scaling is reproduced by turbulent transport: the simulations yield similar λ_q to experimental measurements within a factor of 2. Yet the magnitudes of divertor heat fluxes can be varied, depending on the physics models, sources and sinks, sheath boundary conditions, or flux limiting coefficient; d) Simple estimate by the "2-point model" for λ_q is consistent with simulation. Moreover, blobby turbulent spreading is confirmed for these relatively high B_p shots.

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Research Organization:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Fusion Energy Sciences (FES); National Natural Science Foundation of China (NSFC)

Grant/Contract Number:: AC52-07NA27344; FC02-99ER54512

OSTI ID:: 1566032

Report Number(s):: LLNL-JRNL-722400; 868467; TRN: US2000962

Journal Information:: Nuclear Fusion, Vol. 57, Issue 11; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 34 works

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Experimental study of quasi-coherent mode using EAST tangential CO ₂ laser collective scattering diagnostic in far-forward mode Sun, P. J.; Li, Y. D.; Ren, Y. Physics of Plasmas, Vol. 26, Issue 1 https://doi.org/10.1063/1.5049209	journal	January 2019
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