Measurements of core electron temperature and density fluctuations in DIII-D and comparison to nonlinear gyrokinetic simulations

Journal Article · Thu May 15 00:00:00 EDT 2008 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2895408· OSTI ID:21120371

White, A E; Schmitz, L; Peebles, W A; Carter, T A; Doyle, E J; Rhodes, T L; Wang, G ^[1]; McKee, G R; Shafer, M W ^[2]; Holland, C; Tynan, G R ^[3]; Austin, M E ^[4]; Burrell, K H; Candy, J; DeBoo, J C; Prater, R; Staebler, G M; Waltz, R E ^[5]; Makowski, M A ^[6]

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1. University of California-Los Angeles, Los Angeles, California 90095 (United States)
2. University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
3. University of California-San Diego, La Jolla, California 92093 (United States)
4. University of Texas, Austin, Texas 78712 (United States)
5. General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)
6. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

For the first time, profiles (0.3<{rho}<0.9) of electron temperature and density fluctuations in a tokamak have been measured simultaneously and the results compared to nonlinear gyrokinetic simulations. Electron temperature and density fluctuations measured in neutral beam-heated, sawtooth-free low confinement mode (L-mode) plasmas in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] are found to be similar in frequency and normalized amplitude, with amplitude increasing with radius. The measured radial profile of two fluctuation fields allows for a new and rigorous comparison with gyrokinetic results. Nonlinear gyrokinetic flux-tube simulations predict that electron temperature and density fluctuations have similar normalized amplitudes in L-mode. At {rho}=0.5, simulation results match experimental heat diffusivities and density fluctuation amplitude, but overestimate electron temperature fluctuation amplitude and particle diffusivity. In contrast, simulations at {rho}=0.75 do not match either the experimentally derived transport properties or the measured fluctuation levels.

• OSTI ID: 21120371
• Journal Information: Physics of Plasmas, Vol. 15, Issue 5; Other Information: DOI: 10.1063/1.2895408; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AMPLITUDES
COMPARATIVE EVALUATIONS
DOUBLET-3 DEVICE
ELECTRON DENSITY
ELECTRON TEMPERATURE
FLUCTUATIONS
HEAT
L-MODE PLASMA CONFINEMENT
NONLINEAR PROBLEMS
PLASMA
PLASMA HEATING
PLASMA INSTABILITY
SAWTOOTH OSCILLATIONS
SIMULATION