Multi-field/multi-scale turbulence response to electron cyclotron heating of DIII-D ohmic plasmas

Journal Article · Mon Aug 15 00:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3610552· OSTI ID:22043398

Wang, G; Peebles, W A; Rhodes, T L; Hillesheim, J C; Doyle, E J; Schmitz, L; Zeng, L ^[1]; DeBoo, J C; Staebler, G M; Petty, C C; Burrell, K H; Leonard, A W; VanZeeland, M A ^[2]; Yan, Z; McKee, G R ^[3]; Solomon, W M ^[4]; White, A E ^[5]

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1. Physics and Astronomy Department and PSTI, University of California, Los Angeles, California 90095 (United States)
2. General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)
3. University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
4. Princeton Plasma Physics Lab, Princeton, New Jersey 08543 (United States)
5. Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

The multi-field/multi-scale core ({rho}{approx} 0.5-0.8) turbulence response to electron cyclotron heating (ECH) of DIII-D Ohmic plasmas is reported for the first time. Long wavelength (low-k) electron temperature (T-tilde{sub e}/T{sub e}) and high-k density turbulence levels (n-tilde{sub e}/n{sub e}) are observed to strongly increase during ECH. In contrast, low-k and intermediate-k n-tilde{sub e}/n{sub e} showed little change, whereas the cross-phase between local low-k electron temperature and density fluctuations ({alpha}{sub n{sub eT{sub e}}}) was significantly modified. The increase in the electron thermal diffusivity determined from power balance is consistent with the increased turbulent transport correlated with the measured increases in low-k T-tilde{sub e}/T{sub e} and high-k n-tilde{sub e}/n{sub e}. Linear stability analysis using the trapped gyro-Landau fluid (TGLF) model indicates an enhanced growth rate for electron modes [e.g., trapped electron mode (TEM)] at low-k consistent with the observed modifications in T-tilde{sub e}/T{sub e} and {alpha}{sub n{sub eT{sub e}}}. TGLF also predicts an increase in high-k electron mode growth rates for normalized wavenumbers k{sub {theta}}{rho}{sub s} > 7, where electron temperature gradient (ETG) modes exist, which is consistent with the observed increase in high-kn-tilde{sub e}/n{sub e} turbulence.

• OSTI ID: 22043398
• Journal Information: Physics of Plasmas, Vol. 18, Issue 8; Other Information: (c) 2011 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
CONFINEMENT
DENSITY
DOUBLET-3 DEVICE
ECR HEATING
ELECTRON TEMPERATURE
ION TEMPERATURE
PLASMA
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA SIMULATION
RF SYSTEMS
STABILITY
TEMPERATURE GRADIENTS
THERMAL DIFFUSIVITY
TRANSMISSION ELECTRON MICROSCOPY
TRAPPED ELECTRONS
TRAPPING
TURBULENCE
WAVELENGTHS