Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak
Abstract
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.
- Authors:
-
[1];
- General Atomics, San Diego, CA (United States)
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- National Research Nuclear University MEPhI, Moscow, (Russia). Moscow Engineering Physics Inst.
- Univ. of California, San Diego, CA (United States)
- Publication Date:
- Research Org.:
- General Atomics, San Diego, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES); Russian Science Foundation
- OSTI Identifier:
- 1608578
- Alternate Identifier(s):
- OSTI ID: 1597147; OSTI ID: 1778064
- Report Number(s):
- SAND-2021-4162J
Journal ID: ISSN 1070-664X; TRN: US2105076
- Grant/Contract Number:
- FC02-04ER54698; AC05-06OR23100, FG02-04ER54739; AC04-94AL85000; 18-12-00329; AC05-06OR23100; FG02-04ER54739
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Physics of Plasmas
- Additional Journal Information:
- Journal Volume: 27; Journal Issue: 2; Journal ID: ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Frequency spectrum; Plasma properties and parameters; Magnetohydrodynamics; Plasma confinement; Fusion reactors; Plasma diagnostics; Tokamaks
Citation Formats
Wang, H. Q., Watkins, J. G., Guo, H. Y., Leonard, A. W., Thomas, D. M., Stepanenko, A. A., and Krasheninnikov, S. I. Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak. United States: N. p., 2020.
Web. doi:10.1063/1.5140354.
Wang, H. Q., Watkins, J. G., Guo, H. Y., Leonard, A. W., Thomas, D. M., Stepanenko, A. A., & Krasheninnikov, S. I. Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak. United States. https://doi.org/10.1063/1.5140354
Wang, H. Q., Watkins, J. G., Guo, H. Y., Leonard, A. W., Thomas, D. M., Stepanenko, A. A., and Krasheninnikov, S. I. Tue .
"Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak". United States. https://doi.org/10.1063/1.5140354. https://www.osti.gov/servlets/purl/1608578.
@article{osti_1608578,
title = {Enhanced particle flux due to localized divertor MHD instability in DIII-D tokamak},
author = {Wang, H. Q. and Watkins, J. G. and Guo, H. Y. and Leonard, A. W. and Thomas, D. M. and Stepanenko, A. A. and Krasheninnikov, S. I.},
abstractNote = {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.},
doi = {10.1063/1.5140354},
journal = {Physics of Plasmas},
number = 2,
volume = 27,
place = {United States},
year = {Tue Feb 04 00:00:00 EST 2020},
month = {Tue Feb 04 00:00:00 EST 2020}
}
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