Title: Simulation of divertor heat flux width on EAST by BOUT++ transport code

Abstract

The BOUT++ edge plasma transport code is applied to study the effects of neutral recycling, drifts and heating scheme on edge plasma profiles and the divertor heat flux width of two discharges of the experimental advanced superconducting tokamak (EAST) steady-state H-mode plasmas heated by low hybrid wave (LHW) and neutral beam (NB), respectively. Neutral recycling seems to have played an important role in the plasma density profile. The edge plasma density drops dramatically for the case w/o neutral recycling, while it can be sustained for the case w/ neutral recycling. Drifts are found to have significant influences on edge plasma profiles. Both the amplitude and width of the divertor heat flux are found to have increased a lot due to drifts. The simulated heat flux width w/ drifts for the two discharges shows reasonable agreement with the experiments. However, the width from the simulation and experiment for the LHW heated discharge is much larger than that of the NB heated discharge. Comparison with Goldston's drift-based model and more detailed analysis on the heat flux contributions from drifts versus turbulence show that drifts are the dominant factor in edge plasma transport for both LHW and NB heated discharges, while turbulence maymore » have played a more important role in determining the heat flux width in LHW heated discharges than that in NB heated discharges. This may account for the larger heat flux width in the LHW heated discharge. The magnetic topology and the equilibrium change by the LHW power may also be a potential reason for the larger heat flux width in the LHW heated discharges, which still needs more evidence and studies to support it. Finally, additional SOLPS simulation w/o drifts for the two discharges show reasonable agreement with the counterpart from the BOUT++ simulation, suggesting the two are both suitable codes for EAST edge plasma simulation.« less

Authors:

Deng, G. Z.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6940-0043"

Xu, X. Q. ^[2]; Li, N. M. ^[3]; Liu, X. J. ^[4]; Liu, X. ^[5]; Xu, J. C. ^[4]; Feng, W.  ^[4];

• Search DOE PAGES for author "Feng, W."
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Liu, J. B. ^[5]; Gao, S. L. ^[4]; Liu, S. C. ^[5]; Xia, T. Y. ^[5]; Wang, L. ^[4]

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+ Show Author Affiliations

1. Shenzhen Univ. (China); Chinese Academy of Sciences, Hefei (China); University of Science and Technology of China, Hefei (China); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
3. Dalian Univ. of Technology (China)
4. Chinese Academy of Sciences, Hefei (China); University of Science and Technology of China, Hefei (China)
5. Chinese Academy of Sciences, Hefei (China)

Publication Date:

Tue Jul 21 00:00:00 EDT 2020

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1829593

Alternate Identifier(s):

OSTI ID: 1640253

Report Number(s):

LLNL-JRNL-790439
Journal ID: ISSN 0029-5515; 988986; TRN: US2216402

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Fusion

Additional Journal Information:

Journal Volume: 60; Journal Issue: 8; Journal ID: ISSN 0029-5515

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY