Impurity confinement and transport in high confinement regimes without edge localized modes on DIII-D
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
- Lawerence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53796 (United States)
- Center for Energy Research, University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)
- University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)
Impurity transport in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated in stationary high confinement (H-mode) regimes without edge localized modes (ELMs). In plasmas maintained by resonant magnetic perturbation (RMP), ELM-suppression, and QH-mode, the confinement time of fluorine (Z = 9) is equivalent to that in ELMing discharges with 40 Hz ELMs. For selected discharges with impurity injection, the impurity particle confinement time compared to the energy confinement time is in the range of τ{sub p}/τ{sub e}≈2−3. In QH-mode operation, the impurity confinement time is shown to be smaller for intense, coherent magnetic, and density fluctuations of the edge harmonic oscillation than weaker fluctuations. Transport coefficients are derived from the time evolution of the impurity density profile and compared to neoclassical and turbulent transport models NEO and TGLF. Neoclassical transport of fluorine is found to be small compared to the experimental values. In the ELMing and RMP ELM-suppressed plasma, the impurity transport is affected by the presence of tearing modes. For radii larger than the mode radius, the TGLF diffusion coefficient is smaller than the experimental value by a factor of 2–3, while the convective velocity is within error estimates. Low levels of diffusion are observed for radii smaller than the tearing mode radius. In the QH-mode plasma investigated, the TGLF diffusion coefficient is higher inside of ρ=0.4 and lower outside of 0.4 than the experiment, and the TGLF convective velocity is more negative by a factor of approximately 1.7.
- OSTI ID:
- 22410378
- Journal Information:
- Physics of Plasmas, Vol. 22, Issue 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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