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Main Authors: Paul, Elizabeth J., Hyder, Abdullah, Rodríguez, Eduardo, Jorge, Rogério, Knyazev, Alexey
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2503.03711
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author Paul, Elizabeth J.
Hyder, Abdullah
Rodríguez, Eduardo
Jorge, Rogério
Knyazev, Alexey
author_facet Paul, Elizabeth J.
Hyder, Abdullah
Rodríguez, Eduardo
Jorge, Rogério
Knyazev, Alexey
contents The shear Alfvén wave (SAW) continuum plays a critical role in the stability of energetic particle-driven Alfvén eigenmodes. We develop a theoretical framework to analyze the SAW continuum in three-dimensional quasisymmetric magnetic fields, focusing on its implications for stellarator design. By employing a near-axis model and degenerate perturbation theory, the continuum equation is solved, highlighting unique features in 3D configurations, such as the interactions between spectral gaps. Numerical examples validate the theory, demonstrating the impact of flux surface shaping and quasisymmetric field properties on continuum structure. The results provide insights into optimizing stellarator configurations to minimize resonance-driven losses of energetic particles. This work establishes a basis for incorporating Alfvénic stability considerations into the stellarator design process, demonstrated through optimization of a quasihelical configuration to avoid high-frequency spectral gaps.
format Preprint
id arxiv_https___arxiv_org_abs_2503_03711
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The shear Alfvén continuum of quasisymmetric stellarators
Paul, Elizabeth J.
Hyder, Abdullah
Rodríguez, Eduardo
Jorge, Rogério
Knyazev, Alexey
Plasma Physics
The shear Alfvén wave (SAW) continuum plays a critical role in the stability of energetic particle-driven Alfvén eigenmodes. We develop a theoretical framework to analyze the SAW continuum in three-dimensional quasisymmetric magnetic fields, focusing on its implications for stellarator design. By employing a near-axis model and degenerate perturbation theory, the continuum equation is solved, highlighting unique features in 3D configurations, such as the interactions between spectral gaps. Numerical examples validate the theory, demonstrating the impact of flux surface shaping and quasisymmetric field properties on continuum structure. The results provide insights into optimizing stellarator configurations to minimize resonance-driven losses of energetic particles. This work establishes a basis for incorporating Alfvénic stability considerations into the stellarator design process, demonstrated through optimization of a quasihelical configuration to avoid high-frequency spectral gaps.
title The shear Alfvén continuum of quasisymmetric stellarators
topic Plasma Physics
url https://arxiv.org/abs/2503.03711