Abstract Details
Abstracts
Author: Elizabeth J. Paul
Requested Type: Poster
Submitted: 2023-04-02 14:05:29
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Contact Info:
Columbia University
200 S.W. Mudd, MC4701
New York, NY 10027
USA
Abstract Text:
Magnetic fields with precise levels of quasisymmetry have recently been obtained through numerical optimization, enabling excellent confinement of fusion-born alpha particle trajectories in a stellarator reactor [1]. With the possibility that guiding center orbits can be confined, there is, however, the potential for enhanced losses due to interactions with perturbations in the background plasma, such as shear Alfv'{e}n eigenmodes (AEs). To assess the potential impact, strongly resonant Alfv'{e}nic perturbations are imposed on reactor-scale equilibria close to quasisymmetry, and the guiding center transport is evaluated using the SIMSOPT framework. Kinetic Poincar'{e} plots are used to identify phase-space islands and island overlap. In equilibria that are sufficiently close to quasisymmetry, the symmetry-breaking harmonics do not lead to enhanced transport, while equilibria sufficiently far from quasisymmetry experience enhanced phase-space diffusion. Quasihelical equilibria are found to enjoy reduced AE-driven transport due to the increased spacing between bounce resonances.
[1] M. Landreman and E. J. Paul, Phys. Rev. Lett 128, 035001 (2022).
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