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Title: MHD modeling of a DIII-D low-torque QH-mode discharge and comparison to observations

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4977467· OSTI ID:1347994

Extended-MHD modeling of DIII-D tokamak quiescent H-mode (QH-mode) discharges with nonlinear NIMROD simulations saturates into a turbulent state but does not saturate when the steady-state flow inferred from measurements is not included. This is consistent with the experimental observations of the quiescent regime on DIII-D. The simulation with flow develops into a saturated turbulent state where the nΦ = 1 and 2 toroidal modes become dominant through an inverse cascade. Each mode in the range of nΦ = 1–5 is dominant at a different time. Consistent with experimental observations during QH-mode, the simulated state leads to large particle transport relative to the thermal transport. Analysis shows that the amplitude and phase of the density and temperature perturbations differ resulting in greater fluctuation-induced convective particle transport relative to the convective thermal transport. As a result, comparison to magnetic-coil measurements shows that rotation frequencies differ between the simulation and experiment, which indicates that more sophisticated extended-MHD two-fluid modeling is required.

Research Organization:
Tech-X Corp., Boulder, CO (United States); General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE Office of Nuclear Energy (NE)
Grant/Contract Number:
FC02-06ER54875; AC02-05CH11231; AC02-06CH11357; FC02-04ER54698; FC02-08ER54972
OSTI ID:
1347994
Alternate ID(s):
OSTI ID: 1348026; OSTI ID: 1406354
Journal Information:
Physics of Plasmas, Vol. 24, Issue 5; Conference: manuscript associated with invited talk at APS-DPP Annual Meeting, 2016, in San Jose; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

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Cited By (2)

Physics of increased edge electron temperature and density turbulence during ELM-free QH-mode operation on DIII-D journal May 2018
Access and sustainment of naturally ELM-free and small-ELM regimes journal September 2018