Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak

Wang, H. Q.; Watkins, J. G.; Guo, H. Y.; Leonard, A. W.; Thomas, D. M.; Stepanenko, A. A.; Krasheninnikov, S. I.

doi:10.1063/1.5140354

Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak

Journal Article · Tue Feb 04 00:00:00 EST 2020 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.5140354· OSTI ID:1608578

Wang, H. Q. ^[1]; Watkins, J. G. ^[2]; Guo, H. Y. ^[3]; ^[3]; Thomas, D. M. ^[3]; Stepanenko, A. A. ^[4]; Krasheninnikov, S. I. ^[5]

General Atomics, San Diego, CA (United States); General Atomics, Energy & Advanced Concepts, DIII-D
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
General Atomics, San Diego, CA (United States)
National Research Nuclear University MEPhI, Moscow, (Russia). Moscow Engineering Physics Inst.
Univ. of California, San Diego, CA (United States)

An MHD mode with a frequency of <10 kHz has been identified near the inner strike point from various diagnostics, i.e., divertor Langmuir probes, magnetics sensors, and interferometers, but does not appear in the upstream and core diagnostics. This MHD mode is associated with magnetic oscillations of ≳5 G, has a long wavelength in the toroidal direction with toroidal mode number n=1, but is localized in a narrow radial region of a few cm. The mode appears when the outer strike point remains attached and the inner strike point nearly detaches, grows with increasing density, and eventually weakens and vanishes as the outer strike point detaches. This mode results in particle flux with an order of magnitude higher than the background plasmas near the inner strike point. The mode characteristics are consistent with the Current-Convective-Instability theory prediction. Initial simulations based on experimental input have found oscillations with similar frequencies but weaker amplitude.

View Accepted Manuscript (DOE)

Research Organization:: General Atomics, San Diego, CA (United States); Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

Sponsoring Organization:: Russian Science Foundation; USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

Grant/Contract Number:: AC04-94AL85000; AC05-06OR23100; FC02-04ER54698; FG02-04ER54739

OSTI ID:: 1608578

Alternate ID(s):: OSTI ID: 1778064
OSTI ID: 1597147

Report Number(s):: SAND--2021-4162J

Journal Information:: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 27; ISSN 1070-664X

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

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