2020
1.
Pfefferlé, David; Noakes, Lyle; Zhou, Yao
Rigidity of MHD equilibria to smooth incompressible ideal motion near resonant surfaces Journal Article
In: Plasma Physics and Controlled Fusion, vol. 62, no. 7, pp. 074004, 2020.
Abstract | Links | BibTeX | Tags: Hamiltonian, MHD, MHD equilibrium, perturbation theory, resonant surfaces
@article{pfefferle-rigidityb,
title = {Rigidity of MHD equilibria to smooth incompressible ideal motion near resonant surfaces},
author = {David Pfefferl\'{e} and Lyle Noakes and Yao Zhou},
url = {https://doi.org/10.1088%2F1361-6587%2Fab8ca3},
doi = {10.1088/1361-6587/ab8ca3},
year = {2020},
date = {2020-06-01},
journal = {Plasma Physics and Controlled Fusion},
volume = {62},
number = {7},
pages = {074004},
publisher = {IOP Publishing},
abstract = {In ideal MHD, the magnetic flux is advected by the plasma motion, freezing flux-surfaces into the flow. An MHD equilibrium is reached when the flow relaxes and force balance is achieved. We ask what classes of MHD equilibria can be accessed from a given initial state via smooth incompressible ideal motion. It is found that certain boundary displacements are formally not supported. This follows from yet another investigation of the Hahm\textendashKulsrud\textendashTaylor (HKT) problem, which highlights the resonant behaviour near a rational layer formed by a set of degenerate critical points in the flux-function. When trying to retain the mirror symmetry of the flux-function with respect to the resonant layer, the vector field that generates the volume-preserving diffeomorphism vanishes at the identity to all order in the time-like path parameter.},
keywords = {Hamiltonian, MHD, MHD equilibrium, perturbation theory, resonant surfaces},
pubstate = {published},
tppubtype = {article}
}
In ideal MHD, the magnetic flux is advected by the plasma motion, freezing flux-surfaces into the flow. An MHD equilibrium is reached when the flow relaxes and force balance is achieved. We ask what classes of MHD equilibria can be accessed from a given initial state via smooth incompressible ideal motion. It is found that certain boundary displacements are formally not supported. This follows from yet another investigation of the Hahm–Kulsrud–Taylor (HKT) problem, which highlights the resonant behaviour near a rational layer formed by a set of degenerate critical points in the flux-function. When trying to retain the mirror symmetry of the flux-function with respect to the resonant layer, the vector field that generates the volume-preserving diffeomorphism vanishes at the identity to all order in the time-like path parameter.