Abstract Details
Abstracts
Author: Brady T. Elster
Requested Type: Poster
Submitted: 2025-03-12 14:05:48
Co-authors: Luca Guazzotto
Contact Info:
Auburn University
380 Duncan Drive
Auburn, AL 36832
United States
Abstract Text:
In a two-fluid model of a tokamak plasma, equilibrium rotation is tied to “flow surfaces” that are close to, but distinct from, magnetic surfaces. As a result, the plasma will have an equilibrium velocity component normal to magnetic surfaces which varies with poloidal angle. This normal flow is expected to create qualitative modifications in the behavior of instabilities localized on magnetic surfaces, such as tearing modes. We report on an exploratory investigation of linear tearing mode behavior when equilibrium flow is included in a two-fluid model. Even in the simplified setting of slab geometry, sideband poloidal harmonics are excited by the presence of the normal flow and the layer equation includes new terms that depend on the third derivative of the mode sidebands. Working in Fourier space, with appropriate a priori ordering of the small parameters (resistivity, normal velocity, growth rate), simplifies the calculation enough to allow for solutions that asymptotically match the outer solution. Preliminary results indicate that the effect of equilibrium flow on tearing mode stability could largely depend on the ordering of the small parameters, giving us distinct regimes to examine. Modifications to the tearing stability index Δ′ in various two-fluid equilibrium flow regimes have been derived, but further numerical and analytical work is ongoing to verify these results.
Work supported by DOE grants: DE-SC0023061, DE-SC0024547, DE-SC0014196
Characterization: 1.0
Comments: