First Evidence of Local E×B Drift in the Divertor Influencing the Structure and Stability of Confined Plasma near the Edge of Fusion Devices

Wang, H. Q.; Guo, H. Y.; Xu, G. S.; Leonard, A. W.; Wu, X. Q.; Groth, M.; Jaervinen, A. E.; Watkins, J. G.; Osborne, T. H.; Thomas, D. M.; Eldon, D.; Stangeby, P. C.; Turco, F.; Xu, J. C.; Wang, L.; Wang, Y. F.; Liu, J. B.

doi:10.1103/PhysRevLett.124.195002

First Evidence of Local $E \times B$ Drift in the Divertor Influencing the Structure and Stability of Confined Plasma near the Edge of Fusion Devices

Journal Article · Wed May 13 00:00:00 EDT 2020 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.124.195002· OSTI ID:1630104

^[1]; Guo, H. Y. ^[2]; Xu, G. S. ^[3]; Leonard, A. W. ^[2]; Wu, X. Q. ^[3]; ^[4]; ^[5]; Watkins, J. G. ^[6]; Osborne, T. H. ^[2]; Thomas, D. M. ^[2]; Eldon, D. ^[2]; Stangeby, P. C. ^[7]; Turco, F. ^[8]; ^[9]; Wang, L. ^[3]; Wang, Y. F. ^[3]; Liu, J. B. ^[3]

General Atomics, San Diego, CA (United States); General Atomics
General Atomics, San Diego, CA (United States)
Chinese Academy of Sciences (CAS), Hefei (China)
Aalto Univ., Otaniemi (Finland)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Univ. of Toronto Inst. for Aerospace Studies, ON (United States0
Columbia Univ., New York, NY (United States)
Chinese Academy of Sciences (CAS), Hefei (China); Anhui Univ. of Science and Technology (China)

The structure of the edge plasma in a magnetic confinement system has a strong impact on the overall plasma performance. Here we uncover for the first time a magnetic-field-direction dependent density shelf, i.e., local flattening of density radial profile near the magnetic separatrix, in high confinement plasmas with low edge collisionality in the DIII-D tokamak. The density shelf is correlated with a doubly peaked density profile near the divertor target plate, which tends to occur for operation with the ion BX∇B drift direction away from the X-point, as currently employed for DIII-D advanced tokamak scenarios. This double-peaked divertor plasma profile is connected via the EXB drifts, arising from a strong radial electric field induced by the radial electron temperature gradient near the divertor target. The drifts lead to the reversal of the poloidal flow above the divertor target, resulting in the formation of the density shelf. The edge density shelf can be also enhanced at higher heating power, preventing large, periodic bursts of the plasma, i.e. Edge-localized Modes, in the edge region, consistent with ideal magnetohydrodynamics calculations.

View Accepted Manuscript (DOE)

Research Organization:: General Atomics, San Diego, CA (United States)

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

Grant/Contract Number:: FC02-04ER54698; AC04-94AL85000

OSTI ID:: 1630104

Alternate ID(s):: OSTI ID: 1778067

Journal Information:: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 124; ISSN 0031-9007; ISSN PRLTAO

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

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