Multiconstrained variational problems in magnetohydrodynamics: Equilibrium and slow evolution
A computational method is proposed for solving magnetohydrodynamical equilibrium problems with prescribed flux and mass within the magnetic surfaces that foliate the plasma. Such problems arise in tokamak modeling, for instance, where they determine either equilibria with given adiabatic profiles or...
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Published in | Journal of computational physics Vol. 106; no. 2; pp. 269 - 285 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.06.1993
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Subjects | |
Online Access | Get full text |
ISSN | 0021-9991 1090-2716 |
DOI | 10.1016/S0021-9991(83)71107-1 |
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Summary: | A computational method is proposed for solving magnetohydrodynamical equilibrium problems with prescribed flux and mass within the magnetic surfaces that foliate the plasma. Such problems arise in tokamak modeling, for instance, where they determine either equilibria with given adiabatic profiles or slowly evolving quasi-equilibria governed by the Grad-Hogan equations. The classical variational principles of Kruskal and Kulsrud and Woltjer, which express these problems in terms of energy minimization subject to infinite families of nonlinear, nonlocal constraints, are taken as the basis for a direct method of solution. A natural discretization of the classical constraint families is devised, and an iterative algorithm is developed to solve the resulting optimization problems. A convergence theory for the algorithm is established, and an effective numerical implementation of the method is presented for flux-conserving tokamak equilibria. Some computed examples involving plasma heating and adiabatic compression are described. |
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Bibliography: | None |
ISSN: | 0021-9991 1090-2716 |
DOI: | 10.1016/S0021-9991(83)71107-1 |