April 15-17

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Abstracts

Author: Dylan Langone
Requested Type: Poster
Submitted: 2019-02-22 15:38:53

Co-authors: P.-A. Gourdain, R. Gaur, W. Dorland

Contact Info:
University of Maryland
Department of Physics
College Park, Maryland   20742
United States

Abstract Text:
We assess the ideal ballooning stability properties of a novel, ultra-high beta mode of operation in the ITER geometry. This equilibrium has been shown to be stable to low-n MHD modes, using the DCON code. With a simple MHD ballooning stability code, we identify a region of instability in the subspace of parameter space defined by the magnetic shear and pressure gradient. The equilibrium configuration is confirmed to be stable to ideal ballooning at all radii. The GS2 gyrokinetics code is then used in the long wavelength limit to verify this assessment. We find that GS2 confirms stability of the ideal ballooning mode at nominal parameters of the equilibrium and also recovers the presence of the ideal ballooning instability at the expected, artificially enhanced pressure gradient. At shorter wavelengths (comparable to the ion gyroradius) there are additional micro-instabilities, whose properties remain to be fully elucidated.

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