Characteristics of grassy ELMs and their impact on the divertor heat flux width

Li, Nami; Xu, X. Q.; Wang, Y. F.; Yan, N.; Zhang, J. Y.; Qian, J. P.; Sun, J. Z.; Wang, D. Z.

doi:10.1088/1741-4326/ac83d9

Characteristics of grassy ELMs and their impact on the divertor heat flux width

Journal Article · Tue Aug 16 00:00:00 EDT 2022 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ac83d9· OSTI ID:1893604

^[1]; Xu, X. Q. ^[2]; ^[3]; ^[3]; Zhang, J. Y. ^[3]; Qian, J. P. ^[3]; ^[4]; ^[4]

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Dalian University of Technology (China)
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Chinese Academy of Sciences (CAS), Hefei (China)
Dalian University of Technology (China)

We report BOUT++ turbulence simulations are conducted for a 60 s steady-state long pulse high β_p EAST grassy ELM discharge. BOUT++ linear simulations show that the unstable mode spectrum covers a range of toroidal mode numbers from low-n (n = 10–15) peeling–ballooning modes (P–B) to high-n (n = 40–80) drift-Alfvén instabilities. Nonlinear simulations show that the ELM crash is triggered by low-n peeling modes and fluctuation is generated at the peak pressure gradient position and radially spread outward into the scrape-off-layer, even though the drift-Alfvén instabilities dominate the linear growth phase. However, drift-Alfvén turbulence delays the onset of the grassy ELM and enhances the energy loss with the fluctuation extending to pedestal top region. Simulations further show that if the peeling drive is removed, the fluctuation amplitude drops by an order of magnitude and the ELM crashes disappear. The divertor heat flux width is ~2 times larger than the estimates based on the HD model and the Eich's ITPA multi-tokamak scaling (or empirical Eich scaling) due to the strong radial turbulence transport.

View Accepted Manuscript (DOE)

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

Sponsoring Organization:: Chinese Academy of Science (CAS); National Key R&D Program of China; National Natural Science Foundation of China; USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC52-07NA27344

OSTI ID:: 1893604

Report Number(s):: LLNL-JRNL-833914; 1052270

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 9 Vol. 62; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (36)

Calculation of two-dimension radial electric field in boundary plasmas by using BOUT++ Li, N. M.; Xu, X. Q.; Rognlien, T. D. Computer Physics Communications, Vol. 228 https://doi.org/10.1016/j.cpc.2018.03.003	journal	July 2018
Drift reduced Landau fluid model for magnetized plasma turbulence simulations in BOUT++ framework Zhu, Ben; Seto, Haruki; Xu, Xue-qiao Computer Physics Communications, Vol. 267 https://doi.org/10.1016/j.cpc.2021.108079	journal	October 2021
Broadening of the power fall-off length in a high density, high confinement H-mode regime in ASDEX Upgrade Faitsch, M.; Eich, T.; Harrer, G. F. Nuclear Materials and Energy, Vol. 26 https://doi.org/10.1016/j.nme.2020.100890	journal	March 2021
ELM energy and particle losses and their extrapolation to burning plasma experiments Loarte, A.; Saibene, G.; Sartori, R. Journal of Nuclear Materials, Vol. 313-316 https://doi.org/10.1016/s0022-3115(02)01398-3	journal	March 2003
Numerical studies of edge localized instabilities in tokamaks Wilson, H. R.; Snyder, P. B.; Huysmans, G. T. A. Physics of Plasmas, Vol. 9, Issue 4 https://doi.org/10.1063/1.1459058	journal	April 2002
Simulations of divertor heat flux width using transport code with cross-field drifts under the BOUT++ framework Li, N. M.; Xu, X. Q.; Hughes, J. W. AIP Advances, Vol. 10, Issue 1 https://doi.org/10.1063/1.5126884	journal	January 2020
Scaling studies of the high mode pedestal Groebner, R. J.; Osborne, T. H. Physics of Plasmas, Vol. 5, Issue 5 https://doi.org/10.1063/1.872849	journal	May 1998
Reconstruction of current profile parameters and plasma shapes in tokamaks Lao, L. L.; St. John, H.; Stambaugh, R. D. Nuclear Fusion, Vol. 25, Issue 11 https://doi.org/10.1088/0029-5515/25/11/007	journal	November 1985
D III-D divertor target heat flux measurements during ohmic and neutral beam heating Hill, D. N.; Petrie, T.; Ali Mahdavi, M. Nuclear Fusion, Vol. 28, Issue 5 https://doi.org/10.1088/0029-5515/28/5/015	journal	May 1988
Heuristic drift-based model of the power scrape-off width in low-gas-puff H-mode tokamaks Goldston, R. J. Nuclear Fusion, Vol. 52, Issue 1 https://doi.org/10.1088/0029-5515/52/1/013009	journal	December 2011
Six-field two-fluid simulations of peeling–ballooning modes using BOUT++ Xia, T. Y.; Xu, X. Q.; Xi, P. W. Nuclear Fusion, Vol. 53, Issue 7 https://doi.org/10.1088/0029-5515/53/7/073009	journal	May 2013
Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER Eich, T.; Leonard, A. W.; Pitts, R. A. Nuclear Fusion, Vol. 53, Issue 9 https://doi.org/10.1088/0029-5515/53/9/093031	journal	August 2013
Nonlinear fluid simulation of particle and heat fluxes during burst of ELMs on DIII-D with BOUT++ code Xia, T. Y.; Xu, X. Q. Nuclear Fusion, Vol. 55, Issue 11 https://doi.org/10.1088/0029-5515/55/11/113030	journal	September 2015
Integrated modeling applications for tokamak experiments with OMFIT Meneghini, O.; Smith, S. P.; Lao, L. L. Nuclear Fusion, Vol. 55, Issue 8 https://doi.org/10.1088/0029-5515/55/8/083008	journal	July 2015
Disappearance of giant ELMs and appearance of minute grassy ELMs in JT-60U high-triangularity discharges Kamada, Y.; Oikawa, T.; Lao, L. Plasma Physics and Controlled Fusion, Vol. 42, Issue 5A https://doi.org/10.1088/0741-3335/42/5a/329	journal	May 2000
Edge localized mode characteristics and divertor heat flux during stationary and transient phase for CFETR hybrid scenario Li, Zeyu; Zhu, Yiren; Xu, Guoliang Plasma Physics and Controlled Fusion, Vol. 63, Issue 3 https://doi.org/10.1088/1361-6587/abd25d	journal	January 2021
Investigation of the role of pedestal pressure and collisionality on type-I ELM divertor heat loads in DIII-D Knolker, M.; Bortolon, A.; Canal, G. P. Nuclear Fusion, Vol. 58, Issue 9 https://doi.org/10.1088/1741-4326/aace92	journal	July 2018
Grassy-ELM regime with edge resonant magnetic perturbations in fully noninductive plasmas in the DIII-D tokamak Nazikian, R.; Petty, C. C.; Bortolon, A. Nuclear Fusion, Vol. 58, Issue 10 https://doi.org/10.1088/1741-4326/aad20d	journal	July 2018
Prediction of divertor heat flux width for ITER using BOUT++ transport and turbulence module Li, Ze-Yu; Xu, X. Q.; Li, Na-Mi Nuclear Fusion, Vol. 59, Issue 4 https://doi.org/10.1088/1741-4326/ab0184	journal	February 2019
Simulations on the transient heat fluxes for the low-hybrid wave heating H-mode on EAST Xia, T. Y.; Gui, B.; Huang, Y. Q. Nuclear Fusion, Vol. 59, Issue 7 https://doi.org/10.1088/1741-4326/ab1f15	journal	June 2019
Dependence on plasma shape and plasma fueling for small edge-localized mode regimes in TCV and ASDEX Upgrade Labit, B.; Eich, T.; Harrer, G. F. Nuclear Fusion, Vol. 59, Issue 8 https://doi.org/10.1088/1741-4326/ab2211	journal	June 2019
Simulations of tokamak boundary plasma turbulence transport in setting the divertor heat flux width Xu, X. Q.; Li, N. M.; Li, Z. Y. Nuclear Fusion, Vol. 59, Issue 12 https://doi.org/10.1088/1741-4326/ab430d	journal	October 2019
Achieving a robust grassy-ELM operation regime in CFETR Zhu, Yi-Ren; Li, Ze-Yu; Chan, V. S. Nuclear Fusion, Vol. 60, Issue 4 https://doi.org/10.1088/1741-4326/ab72c0	journal	February 2020
Turbulence driven widening of the near-SOL power width in ASDEX Upgrade H-Mode discharges Eich, T.; Manz, P.; Goldston, R. J. Nuclear Fusion, Vol. 60, Issue 5 https://doi.org/10.1088/1741-4326/ab7a66	journal	April 2020
Stationary high-performance grassy ELM regime in EAST Yang, Q. Q.; Xu, G. S.; Yan, N. Nuclear Fusion, Vol. 60, Issue 7 https://doi.org/10.1088/1741-4326/ab8e0f	journal	June 2020
Non-linear extended MHD simulations of type-I edge localised mode cycles in ASDEX Upgrade and their underlying triggering mechanism Cathey, A.; Hoelzl, M.; Lackner, K. Nuclear Fusion, Vol. 60, Issue 12 https://doi.org/10.1088/1741-4326/abbc87	journal	November 2020
Impact of plasma density/collisionality on divertor heat flux width Li, N. M.; Xu, X. Q.; Goldston, R. J. Nuclear Fusion, Vol. 61, Issue 2 https://doi.org/10.1088/1741-4326/abc839	journal	December 2020
Pedestal stability analysis on MAST in preparation for MAST-U Knolker, M.; Osborne, T.; Belli, E. Nuclear Fusion, Vol. 61, Issue 4 https://doi.org/10.1088/1741-4326/abe804	journal	March 2021
Effects of radial transport on divertor power and particle flux widths under different operational regimes in EAST Deng, G. Z.; Xu, X. Q.; Liu, X. J. Nuclear Fusion, Vol. 61, Issue 10 https://doi.org/10.1088/1741-4326/ac1546	journal	September 2021
Edge-localized-mode simulation in CFETR steady-state scenario Tang, T. F.; Xu, X. Q.; Li, G. Q. Nuclear Fusion, Vol. 62, Issue 1 https://doi.org/10.1088/1741-4326/ac3294	journal	December 2021
Fluid turbulence simulations of divertor heat load for ITER hybrid scenario using BOUT++ Wang, Xueyun; Xu, Xueqiao; Snyder, Philip B. Nuclear Fusion, Vol. 62, Issue 2 https://doi.org/10.1088/1741-4326/ac3b8a	journal	December 2021
EAST steady-state long pulse H-mode with core-edge integration for CFETR Gong, X. Z.; Garofalo, A. M.; Huang, J. Nuclear Fusion, Vol. 62, Issue 7 https://doi.org/10.1088/1741-4326/ac49ad	journal	April 2022
Nonlinear Simulations of Peeling-Ballooning Modes with Anomalous Electron Viscosity and their Role in Edge Localized Mode Crashes Xu, X. Q.; Dudson, B.; Snyder, P. B. Physical Review Letters, Vol. 105, Issue 17 https://doi.org/10.1103/PhysRevLett.105.175005	journal	October 2010
Inter-ELM Power Decay Length for JET and ASDEX Upgrade: Measurement and Comparison with Heuristic Drift-Based Model Eich, T.; Sieglin, B.; Scarabosio, A. Physical Review Letters, Vol. 107, Issue 21 https://doi.org/10.1103/PhysRevLett.107.215001	journal	November 2011
Magnetic Topology Changes Induced by Lower Hybrid Waves and their Profound Effect on Edge-Localized Modes in the EAST Tokamak Liang, Y.; Gong, X. Z.; Gan, K. F. Physical Review Letters, Vol. 110, Issue 23 https://doi.org/10.1103/PhysRevLett.110.235002	journal	June 2013
Emergent Universality in a Quantum Tricritical Dicke Model Xu, Youjiang; Pu, Han Physical Review Letters, Vol. 122, Issue 19 https://doi.org/10.1103/physrevlett.122.193201	journal	May 2019

Similar Records

Turbulence simulations of drift-Alfvén wave effects on edge-localized modes and divertor target heat flux width

Journal Article · Tue Nov 18 19:00:00 EST 2025 · Nuclear Fusion · OSTI ID:3013927

Impact of pedestal density gradient and collisionality on ELM dynamics

Journal Article · Wed Nov 30 19:00:00 EST 2022 · Physics of Plasmas · OSTI ID:1902015

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BOUT++ turbulence
grassy ELM
heat flux width

Characteristics of grassy ELMs and their impact on the divertor heat flux width

Citation Formats

References (36)

Similar Records

Related Subjects