Abstract Details
Abstracts
Author: Hyder S. Abdullah
Requested Type: Poster
Submitted: 2025-03-12 17:17:53
Co-authors: E. Paul, A. Knyazev, D. Spong, H. Yoon
Contact Info:
Columbia University
500 W 120th St
New York, NY 10027
United States
Abstract Text:
In stellarators, gaps arise in the shear Alfvén continuum because of poloidal and toroidal mode coupling through the magnetic geometry. Radially global modes can exist in the gaps, which do not exhibit continuum damping. Continuum damping radially disperses energy gained by shear Alfvén waves. Due to the lack of continuum damping, global Alfvén modes can be driven unstable by energetic particles via inverse Landau damping, potentially leading to instabilities and particle transport. To further understand Alfvénic instabilities and the structure of gaps in stellarators, a broad numerical investigation of the shear Alfvén continuum for several quasi-symmetric (QS) equilibria using Stellgap [1] is presented. Comparisons between analytically and numerically calculated gap widths and gap frequencies are made. Additionally, comparisons are made between relevant geometric parameters and numerically calculated gap widths. Some of the numerical decisions for ensuring sufficient detail while minimizing computational complexity are presented.
[1] D. A. Spong, R. Sanchez, A. Weller; Shear Alfvén continua in stellarators. Phys. Plasmas 1 August 2003; 10 (8): 3217–3224.
Characterization: 4.0
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