Modulation of Core Turbulent Density Fluctuations by Large-Scale Neoclassical Tearing Mode Islands in the DIII-D Tokamak.
We report the first observation of localized modulation of turbulent density fluctuations n[over ˜] (via beam emission spectroscopy) by neoclassical tearing modes (NTMs) in the core of the DIII-D tokamak. NTMs are important as they often lead to severe degradation of plasma confinement and disruptions in high-confinement fusion experiments. Magnetic islands associated with NTMs significantly modify the profiles and turbulence drives. In this experiment n[over ˜] was found to be modulated by 14% across the island. Gyrokinetic simulations suggest that n[over ˜] could be dominantly driven by the ion temperature gradient instability.
University of California Los Angeles, Los Angeles, California 90095, USA.
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Bardóczi
University of California Los Angeles, Los Angeles, California 90095, USA.
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Rhodes
University of California Los Angeles, Los Angeles, California 90095, USA.
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Carter
University of California Los Angeles, Los Angeles, California 90095, USA.
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Bañón Navarro
University of California Los Angeles, Los Angeles, California 90095, USA.
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Peebles
University of California Los Angeles, Los Angeles, California 90095, USA.
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Jenko
University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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McKee