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Title: Representation of ideal magnetohydrodynamic modes

Abstract

One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B(vector sign)={nabla} Multiplication-Sign ({xi}(vector sign) Multiplication-Sign B(vector sign)) ensures that {delta}B(vector sign){center_dot}{nabla}{psi}=0 at a resonance, with {psi} labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation {delta}B(vector sign)={nabla} Multiplication-Sign {alpha}B(vector sign). These two representations are equivalent, but the vanishing of {delta}B(vector sign){center_dot}{nabla}{psi} at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in {xi}(vector sign) to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed.

Authors:
 [1]
  1. Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)
Publication Date:
OSTI Identifier:
22113420
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 20; Journal Issue: 2; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DISTURBANCES; EQUILIBRIUM; MAGNETIC SURFACES; MAGNETOHYDRODYNAMICS; MESONS; PERTURBATION THEORY; PLASMA; PLASMA INSTABILITY; PRESERVATION; STABILITY; TOPOLOGY

Citation Formats

White, R. B. Representation of ideal magnetohydrodynamic modes. United States: N. p., 2013. Web. doi:10.1063/1.4791661.
White, R. B. Representation of ideal magnetohydrodynamic modes. United States. https://doi.org/10.1063/1.4791661
White, R. B. 2013. "Representation of ideal magnetohydrodynamic modes". United States. https://doi.org/10.1063/1.4791661.
@article{osti_22113420,
title = {Representation of ideal magnetohydrodynamic modes},
author = {White, R. B.},
abstractNote = {One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through {delta}B(vector sign)={nabla} Multiplication-Sign ({xi}(vector sign) Multiplication-Sign B(vector sign)) ensures that {delta}B(vector sign){center_dot}{nabla}{psi}=0 at a resonance, with {psi} labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation {delta}B(vector sign)={nabla} Multiplication-Sign {alpha}B(vector sign). These two representations are equivalent, but the vanishing of {delta}B(vector sign){center_dot}{nabla}{psi} at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in {xi}(vector sign) to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed.},
doi = {10.1063/1.4791661},
url = {https://www.osti.gov/biblio/22113420}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 2,
volume = 20,
place = {United States},
year = {Fri Feb 15 00:00:00 EST 2013},
month = {Fri Feb 15 00:00:00 EST 2013}
}