Suppression of Electron Temperature Gradient Turbulence via Negative Magnetic Shear in NSTX

Journal Article · Fri Feb 04 00:00:00 EST 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.106.055003· OSTI ID:21532283

Yuh, H Y; Levinton, F M ^[1]; Kaye, S M; Mazzucato, E; Mikkelsen, D R; Bell, R E; Hosea, J C; LeBlanc, B P; Peterson, J L ^[2]; Smith, D R ^[3]; Park, H K; Lee, W ^[4]

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1. Nova Photonics Inc., Princeton, New Jersey 08540 (United States)
2. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
3. Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
4. POSTECH, Pohang 790-784 (Korea, Republic of)

Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible ExB shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms.

• OSTI ID: 21532283
• Journal Information: Physical Review Letters, Vol. 106, Issue 5; Other Information: DOI: 10.1103/PhysRevLett.106.055003; (c) 2011 American Institute of Physics; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DENSITY
ELECTROMAGNETIC FIELDS
ELECTRON TEMPERATURE
FLUCTUATIONS
NSTX DEVICE
SHEAR
SPHERICAL CONFIGURATION
TEMPERATURE GRADIENTS
THERMAL DIFFUSIVITY
TURBULENCE
CLOSED PLASMA DEVICES
CONFIGURATION
PHYSICAL PROPERTIES
SPHEROMAK DEVICES
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VARIATIONS