Abstract Details
Abstracts
Author: Wrick Sengupta
Requested Type: Consider for Invited
Submitted: 2023-03-25 06:05:30
Co-authors: N. Nikulsin, E.J. Paul, S. Buller, R. Nies, S.R. Hudson, A. Bhattacharjee
Contact Info:
Princeton University
4 Ivy Lane
Princeton, New Jersey 08544
United States
Abstract Text:
Quasisymmetry (QS) is a hidden symmetry of the magnetic field strength, B, that confines charged particles effectively in a nonsymmetric toroidal plasma equilibrium. Recent numerical breakthroughs have shown that excellent QS can be realized in a toroidal volume. Here, we show that the hidden symmetry of QS has a deep connection to the underlying symmetry that makes solitons possible. In particular, we demonstrate that a class of quasisymmetric B is described by a periodic finite-gap soliton potential of the well-known Korteweg-de Vries (KdV) equation. Our exact and non-perturbative method drastically reduces the number of independent B parameters on a magnetic flux surface to just three, which could make stellarator optimization schemes significantly more efficient. Furthermore, we deduce an upper bound on the maximum toroidal volume that can be quasisymmetric. B approaches the form of the 1-soliton reflectionless potential in the neighborhood of the outermost surface. Finally, we discuss various extensions of this work, which enforces ideal magnetohydrostatic force balance conditions in slab and large aspect ratio torus geometries.
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