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arxiv: 2506.09787 · v2 · submitted 2025-06-11 · 🧮 math-ph · math.MP· physics.plasm-ph

Metriplectic relaxation to equilibria

Pith reviewed 2026-05-19 10:02 UTC · model grok-4.3

classification 🧮 math-ph math.MPphysics.plasm-ph
keywords metriplectic systemsLandau operatorentropy dissipationrelaxation to equilibriumplasma physicsfluid dynamics
0
0 comments X p. Extension

The pith

Metriplectic systems converge to entropy extrema on constant-Hamiltonian surfaces when two simpler conditions hold for a Landau-inspired bracket class.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper sets out sufficient conditions under which metriplectic dynamics, built from a Hamiltonian part and an entropy-gradient flow, drive orbits to an extremum of entropy while keeping the Hamiltonian fixed. It then introduces a family of brackets modeled on the Landau operator for Coulomb collisions in plasmas. For brackets in this family the general convergence conditions collapse to two checks that are easier to verify. The construction is used to create relaxation flows that find equilibria in fluid and plasma models by letting the system evolve until entropy is maximized at fixed energy.

Core claim

Metriplectic dynamical systems combine a Hamiltonian vector field with a generalized entropy gradient flow so that the Hamiltonian is conserved while entropy is dissipated or produced. Sufficient conditions are given for the long-time orbit to reach an extremum of entropy on a level set of the Hamiltonian. A class of brackets inspired by the Landau collision operator is constructed; within this class the convergence criteria reduce to verification of two simpler conditions. These brackets are applied to build relaxation methods that solve equilibrium problems in fluid dynamics and plasma physics.

What carries the argument

Metriplectic bracket that pairs a Poisson structure with a dissipative term derived from an entropy function, specialized to a Landau-inspired form whose convergence reduces to two checks.

If this is right

  • Equilibrium problems in ideal fluid dynamics can be solved by evolving the metriplectic relaxation flow until it stops.
  • Plasma equilibrium configurations can be recovered as long-time limits of the constructed Landau-type brackets.
  • Convergence verification for the entire family reduces to checking two bracket properties instead of the full set of general conditions.
  • The same bracket construction supplies a systematic way to generate entropy-dissipating dynamics that preserve a chosen Hamiltonian.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same reduction technique might simplify convergence proofs for other dissipative brackets outside the Landau family.
  • Relaxation methods built this way could be combined with existing structure-preserving integrators to improve numerical stability.
  • If the two conditions are easy to check in practice, the approach offers a practical alternative to direct minimization of entropy subject to Hamiltonian constraints.

Load-bearing premise

The specific metriplectic brackets must satisfy the general sufficient conditions for convergence that the paper states earlier.

What would settle it

Numerical integration of a Landau-inspired metriplectic system that meets the two reduced conditions but fails to approach the predicted entropy extremum at fixed Hamiltonian.

Figures

Figures reproduced from arXiv: 2506.09787 by C. Bressan, M. Kraus, O. Maj, P. J. Morrison.

Figure 1
Figure 1. Figure 1: Example of solution of Eq. (59) with Hamiltonian (60). Upper panels: initial condition and final state, compared to the contours of h (black circular curves). Lower panel: A visualization of the functional relation between h and u obtained by plotting the points (hij , uij ), with hij and uij being the values of h and u, at the node (i, j) of the computational grid. (For clarity, in the color maps we displ… view at source ↗
Figure 2
Figure 2. Figure 2: Metriplectic relaxation of a vortex toward an equilibrium of the reduced Euler equations, [PITH_FULL_IMAGE:figures/full_fig_p044_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Visualization of the relation between the potential [PITH_FULL_IMAGE:figures/full_fig_p045_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: The same as in Fig [PITH_FULL_IMAGE:figures/full_fig_p048_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Left-hand-side panel: the relation between [PITH_FULL_IMAGE:figures/full_fig_p049_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Left-hand-side panel: trajectory in the plane ( [PITH_FULL_IMAGE:figures/full_fig_p050_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: The same as in Fig [PITH_FULL_IMAGE:figures/full_fig_p051_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Construction of the operators P and P ′ in Eqs. (69) and (71). If u ∈ C 1 ([0, T], V ) is a trajectory in V and F ∈ C 1 (V ) has a functional derivative δF(u)/δu in Φ, then t 7→ F u(t)  is differentiable and d dtF [PITH_FULL_IMAGE:figures/full_fig_p052_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Relaxation of an initial vortex with initial vorticity given in Eq. ( [PITH_FULL_IMAGE:figures/full_fig_p062_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Evolution of entropy (left-hand-side panel) and of the variation of the Hamiltonian relative [PITH_FULL_IMAGE:figures/full_fig_p062_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: The same as Fig [PITH_FULL_IMAGE:figures/full_fig_p063_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: Evolution of entropy (left-hand-side panel) and of the variation of the Hamiltonian relative [PITH_FULL_IMAGE:figures/full_fig_p063_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: The same as Fig [PITH_FULL_IMAGE:figures/full_fig_p064_13.png] view at source ↗
Figure 14
Figure 14. Figure 14: Evolution of entropy (left-hand-side panel) and of the variation of the Hamiltonian relative [PITH_FULL_IMAGE:figures/full_fig_p065_14.png] view at source ↗
Figure 15
Figure 15. Figure 15: Relaxation of an initial current Jφ = (c/4πr)u0, with u0 Gaussian, according to the evolution equation (84) applied to the Grad-Shafranov problem (20) with entropy (91) on a rectangular domain. The initial condition and the final state of the system are given in left-hand-side and middle panels, respectively, while the right-hand side panel shows the scatter plot, with the same color/symbol code as in [P… view at source ↗
Figure 16
Figure 16. Figure 16: Evolution of entropy (left-hand-side panel) and of the variation of the Hamiltonian relative [PITH_FULL_IMAGE:figures/full_fig_p066_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: The same as in Fig [PITH_FULL_IMAGE:figures/full_fig_p067_17.png] view at source ↗
Figure 18
Figure 18. Figure 18: Evolution of entropy (left-hand-side panel) and of the variation of the Hamiltonian relative [PITH_FULL_IMAGE:figures/full_fig_p067_18.png] view at source ↗
Figure 19
Figure 19. Figure 19: Poincar´e plot in the plane x1-x2 and selected field lines of the magnetic field B, for the initial condition (top row) and the final state (bottom row), after the relaxation process. The initial condition is given in Eq. (101) with m = n = 1 and a = 1, while the evolution equation is the magneto-frictional method (99). The selected field lines correspond to the four large islands visible in the Poincar´e… view at source ↗
Figure 20
Figure 20. Figure 20: From top to bottom, time evolution of the entropy (magnetic energy), the relative variation [PITH_FULL_IMAGE:figures/full_fig_p075_20.png] view at source ↗
read the original abstract

Metriplectic dynamical systems consist of a special combination of a Hamiltonian and a (generalized) entropy-gradient flow, such that the Hamiltonian is conserved and entropy is dissipated/produced (depending on a sign convention). It is natural to expect that, in the long-time limit, the orbit of a metriplectic system should converge to an extremum of entropy restricted to a constant-Hamiltonian surface. In this paper, we discuss sufficient conditions for this to occur. Then, we construct a class of metriplectic systems inspired by the Landau operator for Coulomb collisions in plasmas, which is included as special case. For this class of brackets, checking the conditions for convergence reduces to checking two usually simpler conditions, and we discuss examples in detail. We apply these results to the construction of relaxation methods for the solution of equilibrium problems in fluid dynamics and plasma physics.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 2 minor

Summary. The manuscript establishes general sufficient conditions for long-time convergence of metriplectic orbits to entropy extrema on level sets of the Hamiltonian. It then constructs a Landau-inspired family of brackets for which those conditions reduce to two simpler, explicitly checkable properties (typically involving positivity or definiteness of operators derived from the collision kernel). The full text supplies the algebraic verification that the constructed brackets satisfy the background degeneracy and compatibility requirements, together with detailed examples in fluid and plasma models where the two reduced conditions are confirmed by direct computation.

Significance. If the sufficient conditions and the reduction hold, this provides a systematic way to construct metriplectic relaxation methods for equilibrium problems in fluid dynamics and plasma physics. The algebraic verification that the constructed brackets satisfy the degeneracy and compatibility requirements, together with the explicit confirmation of the two reduced conditions in the examples, is a clear strength that makes the framework directly usable.

minor comments (2)
  1. The abstract states that sufficient conditions exist and that the new class reduces the check to two simpler conditions, but does not name those conditions; adding one sentence identifying them would improve the summary.
  2. Notation for the metriplectic brackets and the derived operators should be introduced with explicit definitions on first appearance to aid readers outside the immediate subfield.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive and constructive report, which accurately captures the main contributions of the manuscript. We appreciate the recommendation for minor revision and are prepared to incorporate any editorial or minor clarifications that may be suggested.

Circularity Check

0 steps flagged

No significant circularity; derivation is self-contained via independent mathematical conditions and verifications

full rationale

The paper first derives general sufficient conditions for long-time convergence of metriplectic orbits to entropy extrema on constant-Hamiltonian surfaces. It then constructs a Landau-inspired class of brackets and supplies explicit algebraic verification that the constructed brackets satisfy the background degeneracy, compatibility, and positivity requirements, reducing the general checks to two simpler, directly computable properties. Detailed examples in fluid and plasma models confirm these properties by direct computation. No step reduces by construction to a fitted input, self-definition, or unverified self-citation chain; the central results rest on stated assumptions and explicit derivations that remain falsifiable outside any fitted values.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claims rest on the standard definition of metriplectic systems (Hamiltonian conservation plus entropy dissipation) and on the assumption that the constructed brackets belong to the Landau-inspired family; no free parameters or new invented entities are mentioned.

axioms (2)
  • domain assumption Metriplectic systems conserve the Hamiltonian while dissipating or producing entropy according to a generalized gradient flow.
    Invoked in the opening definition of metriplectic dynamical systems in the abstract.
  • domain assumption Long-time orbits converge to an extremum of entropy on the constant-Hamiltonian surface under sufficient conditions.
    Stated as the natural expectation that the paper then provides conditions for.

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Metriplectic dynamical systems on contact manifolds

    math.SG 2026-05 unverdicted novelty 5.0

    A metriplectic flow on J¹N = T*N × ℝ enforces Ḣ = 0 and Ṡ ≥ 0, extending contact Hamiltonian dynamics to thermodynamically consistent systems, as shown for the Duffing equation.

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Works this paper leans on

114 extracted references · 114 canonical work pages · cited by 1 Pith paper

  1. [1]

    P. J. Morrison, Bracket formulation for irreversible classical fields, Physics Letters A 100 (8) (1984) 423 – 427. doi:10.1016/0375-9601(84)90635-2

  2. [2]

    P. J. Morrison, Some observations regarding brackets and dissipation, Tech. Rep. PAM–228, Uni- versity of California at Berkeley, available at arXiv:2403.14698v1 [mathph] 15 Mar 2024 (March 1984)

  3. [3]

    P. J. Morrison, A paradigm for joined Hamiltonian and dissipative systems, Physica D: Nonlinear Phenomena 18 (1986) 410–419. doi:10.1016/0167-2789(86)90209-5. 81

  4. [4]

    P. J. Morrison, Hamiltonian description of the ideal fluid, Rev. Mod. Phys. 70 (1998) 467–521. doi:10.1103/RevModPhys.70.467

  5. [5]

    J. P. Freidberg, Ideal MHD, Cambridge University Press, 2014. doi:10.1017/CBO9780511795046

  6. [6]

    O. P. Bruno, P. Laurence, Existence of three-dimensional toroidal MHD equilibria with non- constant pressure, Communications on Pure and Applied Mathematics 49 (7) (1996) 717–764. doi:10.1002/(SICI)1097-0312(199607)49:7<717::AID-CPA3>3.0.CO;2-C

  7. [7]

    Bauer, O

    F. Bauer, O. Betancourt, P. Garabedian, A Computational Method in Plasma Physics, Springer- Verlag, 1978. doi:10.1007/978-3-642-85470-5

  8. [8]

    S. P. Hirshman, J. C. Whitson, Steepest-descent moment method for three-dimensional magneto- hydrodynamic equilibria, Physics of Fluids 26 (12) (1983) 3553–3568. doi:10.1063/1.864116

  9. [9]

    Imbert-G´ erard, E

    L.-M. Imbert-G´ erard, E. J. Paul, A. M. Wright, An Introduction to Stellarators: From Magnetic Fields to Symmetries and Optimization, Society for Industrial and Applied Mathematics, 2024. doi:https://doi.org/10.1137/1.9781611978223

  10. [10]

    H. Grad, H. Rubin, Hydromagnetic equilibria and force-free fields, Journal of Nuclear Energy (1954) 7 (3-4) (1958) 284–285

  11. [11]

    Reiman, H

    A. Reiman, H. Greenside, Calculation of three-dimensional MHD equilibria with islands and stochastic regions, Computer Physics Communications 43 (1) (1986) 157 – 167. doi:10.1016/ 0010-4655(86)90059-7

  12. [12]

    H. K. Moffatt, Magnetostatic equilibria and analogous Euler flows of arbitrarily complex topol- ogy. part 1. fundamentals, Journal of Fluid Mechanics 159 (1985) 359–378. doi:10.1017/ S0022112085003251

  13. [13]

    V. I. Arnold, B. A. Khesin, Topological Methods in Hydrodynamics, Springer-Verlag, 1998

  14. [14]

    Moffatt, Some topological aspects of fluid dynamics, Journal of Fluid Mechanics 914 (2021) P1

    H. Moffatt, Some topological aspects of fluid dynamics, Journal of Fluid Mechanics 914 (2021) P1. doi:10.1017/jfm.2020.230

  15. [15]

    Alfv´ en, Existence of electromagnetic-hydrodynamic waves, Nature 150 (1942) 405–406

    H. Alfv´ en, Existence of electromagnetic-hydrodynamic waves, Nature 150 (1942) 405–406. doi: 10.1038/150405d0

  16. [16]

    Harafuji, T

    K. Harafuji, T. Hayashi, T. Sato, Computational study of three-dimensional magnetohydrody- namic equilibria in toroidal helical systems, Journal of Computational Physics 81 (1) (1989) 169–

  17. [17]

    doi:10.1016/0021-9991(89)90069-7

  18. [18]

    Suzuki, N

    Y. Suzuki, N. Nakajima, K. Watanabe, et al., Development and application of HINT2 to helical system plasmas, Nuclear Fusion 46 (11) (2006) L19. doi:10.1088/0029-5515/46/11/L01

  19. [19]

    Chodura, A

    R. Chodura, A. Schlueter, A 3D code for MHD equilibrium and stability, Journal of Computational Physics 41 (1) (1981) 68 – 88. doi:10.1016/0021-9991(81)90080-2

  20. [20]

    Wiegelmann, T

    T. Wiegelmann, T. Sakurai, Solar force-free magnetic fields, Living Reviews in Solar Physics 9 (1) (2012) 5. doi:10.1007/s41116-020-00027-4

  21. [21]

    Brenier, X

    Y. Brenier, X. Duan, An integrable example of gradient flow based on optimal transport of differential forms, Calculus of Variations and Partial Differential Equations 57 (5) (2018) 125. doi:10.1007/s00526-018-1370-6

  22. [22]

    S. P. Hirshman, R. Sanchez, C. R. Cook, SIESTA: A scalable iterative equilibrium solver for toroidal applications, Physics of Plasmas 18 (6), 062504 (2011). doi:10.1063/1.3597155

  23. [23]

    Coquinot, P

    B. Coquinot, P. J. Morrison, A general metriplectic framework with application to dissipative extended magnetohydrodynamics, Journal of Plasma Physics 86 (3) (2020) 835860302. doi:10. 1017/s0022377820000392

  24. [24]

    P. J. Morrison, M. H. Updike, Inclusive curvature-like framework for describing dissipation: Metriplectic 4-bracket dynamics, Physical Review E 109 (2024) 045202

  25. [25]

    Zaidni, P

    A. Zaidni, P. J. Morrison, S. Benjelloun, Thermodynamically consistent Cahn–Hilliard–Navier–Stokes equations using the metriplectic dynamics formalism, Physica D 468 (2024) 134303. doi:https://doi.org/10.1016/j.physd.2024.134303

  26. [26]

    N. Sato, P. J. Morrison, A collision operator for describing dissipation in noncanonical phase space, Fund. Plasma Phys. 10 (2024) 100054

  27. [27]

    Zaidni, P

    A. Zaidni, P. J. Morrison, Metriplectic 4-bracket algorithm for constructing thermodynamically consistent dynamical systems, arXiv (2024) arXiv:2412. arXiv:\physics.comp-ph/2412

  28. [28]

    M. W. Hirsch, S. Smale, R. L. Devaney, Differential Equations, Dynamical Systems, and an Intro- duction to Chaos, third edition Edition, Elsevier, 2013. doi:10.1016/C2009-0-61160-0

  29. [29]

    Materassi, Metriplectic algebra for dissipative fluids in Lagrangian formulation, Entropy 17 (3) (2015) 1329–1346

    M. Materassi, Metriplectic algebra for dissipative fluids in Lagrangian formulation, Entropy 17 (3) (2015) 1329–1346. doi:10.3390/e17031329

  30. [30]

    Materassi, E

    M. Materassi, E. Tassi, Metriplectic framework for dissipative magneto-hydrodynamics, Physica D: Nonlinear Phenomena 241 (6) (2012) 729–734. doi:10.1016/j.physd.2011.12.013

  31. [31]

    Kraus, E

    M. Kraus, E. Hirvijoki, Metriplectic integrators for the Landau collision operator, Physics of 82 Plasmas 24 (10) (2017) 102311. doi:10.1063/1.4998610

  32. [32]

    Barham, P

    W. Barham, P. J. Morrison, A. Zaidni, A thermodynamically consistent discretization of 1D thermal-fluid models using their metriplectic 4-bracket structure, Communications in Nonlinear Science and Numerical Simulation 145 (2025) 108683. URL https://www.sciencedirect.com/science/article/pii/S1007570425000942

  33. [33]

    G. K. Vallis, G. G. Carnevale, W. R. Young, Extremal energy properties and construction of stable solutions of the Euler equations, J. Fluid Mech. 207 (1989) 133–152. doi:https://doi.org/10. 1017/S0022112089002533

  34. [34]

    G. G. Carnevale, G. K. Vallis, Pseudo-advective relaxation to stable states of inviscid two-dimensional fluids, J. Fluid Mech. 213 (1990) 549–571. doi:https://doi.org/10.1017/ S0022112090002440

  35. [35]

    Nonlinear Excursions

    G. Flierl, P. Morrison, Hamiltonian Dirac simulated annealing: Application to the calculation of vortex states, Physica D: Nonlinear Phenomena 240 (2) (2011) 212 – 232, “Nonlinear Excursions” Symposium and Volume in Physica D to honor Louis N. Howard’s scientific career. doi:10.1016/ j.physd.2010.08.011

  36. [36]

    Chikasue, M

    Y. Chikasue, M. Furukawa, Adjustment of vorticity fields with specified values of Casimir invariants as initial condition for simulated annealing of an incompressible, ideal neutral fluid and its mhd in two dimensions, Journal of Fluid Mechanics 774 (2015) 443–459. doi:10.1017/jfm.2015.263

  37. [37]

    Chikasue, M

    Y. Chikasue, M. Furukawa, Simulated annealing applied to two-dimensional low-beta reduced magnetohydrodynamics, Physics of Plasmas (1994-present) 22 (2) (2015).doi:10.1063/1.4913234

  38. [38]

    Furukawa, P

    M. Furukawa, P. J. Morrison, Simulated annealing for three-dimensional low-beta reduced MHD equilibria in cylindrical geometry, Plasma Physics and Controlled Fusion 59 (5) (2017) 054001. doi:10.1088/1361-6587/aa5863

  39. [39]

    Furukawa, T

    M. Furukawa, T. Watanabe, P. J. Morrison, et al., Calculation of large-aspect-ratio tokamak and toroidally-averaged stellarator equilibria of high-beta reduced magnetohydrodynamics via simu- lated annealing, Physics of Plasmas 25 (8) (2018) 082506. doi:10.1063/1.5038043

  40. [40]

    Furukawa, P

    M. Furukawa, P. J. Morrison, Simulated annealing of reduced magnetohydrodynamic systems, Reviews of Modern Plasma Physics 9 (1) (2025) 15. URL https://doi.org/10.1007/s41614-025-00185-8

  41. [41]

    Brockett, Dynamical systems that sort lists, diagonalize matrices, and solve linear programming problems, Linear Algebra and its Applications 146 (1991) 79–91

    R. Brockett, Dynamical systems that sort lists, diagonalize matrices, and solve linear programming problems, Linear Algebra and its Applications 146 (1991) 79–91. doi:10.1109/cdc.1988.194420

  42. [42]

    A. M. Bloch, R. W. Brockett, T. S. Ratiu, Completely integrable gradient flows, Communications in Mathematical Physics 147 (1) (1992) 57–74. doi:10.1007/bf02099528

  43. [43]

    A. M. Bloch, P. J. Morrison, T. S. Ratiu, Flows in the normal and Kaehler metrics and triple bracket generated metriplectic systems, in Recent Trends in Dynamical Systems, eds. A. Johann et al., Springer Proceedings in Mathematics & Statistics 35 (2013) 371–415

  44. [44]

    Hasegawa, Self-organization processes in continuous media, Advances in Physics 34 (1) (1985) 1–42

    A. Hasegawa, Self-organization processes in continuous media, Advances in Physics 34 (1) (1985) 1–42. doi:10.1080/00018738500101721

  45. [45]

    Yoshida, S

    Z. Yoshida, S. M. Mahajan, Variational principles and self-organization in two-fluid plasmas, Phys. Rev. Lett. 88 (2002) 095001. doi:10.1103/PhysRevLett.88.095001

  46. [46]

    Woltjer, On hydromagnetic equilibrium, Proceedings of the National Academy of Sciences 44 (9) (1958) 833–841

    L. Woltjer, On hydromagnetic equilibrium, Proceedings of the National Academy of Sciences 44 (9) (1958) 833–841. doi:10.1073/pnas.44.9.833

  47. [47]

    J. B. Taylor, Relaxation of toroidal plasma and generation of reverse magnetic fields, Phys. Rev. Lett. 33 (1974) 1139–1141. doi:10.1103/PhysRevLett.33.1139

  48. [48]

    J. B. Taylor, Relaxation and magnetic reconnection in plasmas, Rev. Mod. Phys. 58 (1986) 741–

  49. [49]

    doi:10.1103/revmodphys.58.741

  50. [50]

    H. Qin, W. Liu, H. Li, et al., Woltjer-Taylor state without Taylor’s conjecture: Plasma relaxation at all wavelengths, Phys. Rev. Lett. 109 (2012) 235001. doi:10.1103/PhysRevLett.109.235001

  51. [51]

    M. F. Adams, E. Hirvijoki, M. G. Knepley, et al., Landau collision integral solver with adaptive mesh refinement on emerging architectures, SIAM Journal on Scientific Computing 39 (6) (2017) C452–C465. doi:10.1137/17M1118828

  52. [52]

    Gay-Balmaz, D

    F. Gay-Balmaz, D. D. Holm, Selective decay by Casimir dissipation in inviscid fluids, Nonlinearity 26 (2) (2013) 495. doi:10.1088/0951-7715/26/2/495

  53. [53]

    Gay-Balmaz, D

    F. Gay-Balmaz, D. D. Holm, A geometric theory of selective decay with applications in MHD, Nonlinearity 27 (8) (2014) 1747. doi:10.1088/0951-7715/27/8/1747

  54. [54]

    J. K. Hunter, B. Nachtergaele, Applied Analysis, World Scientific Publishing Company, 2001

  55. [55]

    J. E. Marsden, T. Ratiu, R. Abraham, Manifolds, Tensor Analysis, and Applications, third edition Edition, Springer, 2001

  56. [56]

    P. J. Morrison, Poisson brackets for fluids and plasmas, Cont. Math. 88 (1982) 13–46. doi: 83 10.1063/1.33633

  57. [57]

    P. J. Morrison, S. Eliezer, Spontaneous symmetry breaking and neutral stability in the noncanon- ical Hamiltonian formalism, Phys. Rev. A 33 (1986) 4205–4214

  58. [58]

    Yoshida, T

    Z. Yoshida, T. Tokieda, P. J. Morrison, Rattleback: A model of how geometric singularity induces dynamic chirality, Phys. Lett. A 381 (2017) 2772–2777

  59. [59]

    Yoshida, P

    Z. Yoshida, P. J. Morrison, Deformation of Lie-Poisson algebras and chirality, J. Math. Phys. 61 (2020) 082901

  60. [60]

    Yoshida, P

    Z. Yoshida, P. J. Morrison, Hierarchical structure of noncanonical Hamiltonian systems, Physica Scripta 91 (2) (2016) 024001. doi:10.1088/0031-8949/91/2/024001

  61. [61]

    M. E. Taylor, Partial Differential Equations III: Nonlinear Equations, Vol. 117 of Applied Mathe- matical Sciences, Springer New York, 2011. doi:10.1007/978-1-4419-7049-7

  62. [62]

    Takeda, S

    T. Takeda, S. Tokuda, Computation of MHD equilibrium of tokamak plasma, Journal of Compu- tational Physics 93 (1) (1991) 1 – 107. doi:10.1016/0021-9991(91)90074-u

  63. [63]

    M. E. Taylor, Partial Differential Equations I: Basic Theory, Vol. 115 of Applied Mathematical Sciences, Springer New York, 2011. doi:10.1007/978-1-4419-7055-8

  64. [64]

    M. D. Kruskal, R. M. Kulsrud, Equilibrium of a magnetically confined plasma in a toroid, Physics of Fluids 1 (4) (1958) 265–274. doi:10.1063/1.1705884

  65. [65]

    Grad, Some new variational properties of hydromagnetic equilibria, Physics of Fluids 7 (8) (1964) 1283–1292

    H. Grad, Some new variational properties of hydromagnetic equilibria, Physics of Fluids 7 (8) (1964) 1283–1292. doi:10.1063/1.1711373

  66. [66]

    L. L. LoDestro, L. D. Pearlstein, On the Grad-Shafranov equation as an eigenvalue problem, with implications for q solvers, Physics of Plasmas 1 (1) (1994) 90–95. doi:10.1063/1.870464

  67. [67]

    Pataki, A

    A. Pataki, A. J. Cerfon, J. P. Freidberg, et al., A fast, high-order solver for the Grad-Shafranov equation, Journal of Computational Physics 243 (2013) 28–45. doi:10.1016/j.jcp.2013.02.045

  68. [68]

    Yoshida, Y

    Z. Yoshida, Y. Giga, Remarks on spectra of operator rot, Mathematische Zeitschrift 204 (1) (1990) 235–245. doi:10.1007/BF02570870

  69. [69]

    Boulmezaoud, Y

    T.-Z. Boulmezaoud, Y. Maday, T. Amari, On the linear force-free fields in bounded and unbounded three-dimensional domains, ESAIM: M2AN 33 (2) (1999) 359–393. doi:10.1051/m2an:1999121

  70. [70]

    R. L. Dewar, M. J. Hole, M. McGann, et al., Relaxed plasma equilibria and entropy-related plasma self-organization principles, Entropy 10 (4) (2008) 621–634. doi:10.3390/e10040621. URL http://dx.doi.org/10.3390/e10040621

  71. [71]

    S. R. Hudson, R. L. Dewar, G. Dennis, et al., Computation of multi-region relaxed magnetohy- drodynamic equilibria, Physics of Plasmas 19 (11) (2012) 112502. arXiv:http://dx.doi.org/10. 1063/1.4765691, doi:10.1063/1.4765691

  72. [72]

    A. M. Dixon, M. A. Berger, P. K. Browning, E. R. Priest, A generalization of the Woltjer minimum- energy principle, Astron. Astrophys. 225 (1989) 156–166

  73. [73]

    Laurence, M

    P. Laurence, M. Avellaneda, On Woltjer’s variational principle for force-free fields, Journal of Mathematical Physics 32 (5) (1991) 1240–1253. doi:10.1063/1.529321

  74. [74]

    H. K. Moffatt, The degree of knottedness of tangled vortex lines, Journal of Fluid Mechanics null (1969) 117–129. doi:10.1017/s0022112069000991

  75. [75]

    V. I. Arnold, The asymptotic Hopf invariant and its applications, Springer Berlin Heidelberg, Berlin, Heidelberg, 2014, pp. 357–375. doi:10.1007/978-3-642-31031-7_32

  76. [76]

    Vogel, On the asymptotic linking number, Proc

    T. Vogel, On the asymptotic linking number, Proc. of the American Mathematical Society 131 (7) (2003) 2289–2297. doi:10.1090/s0002-9939-02-06792-8

  77. [77]

    P. C. Kendall, The variational formulation of the magneto-hydrostatic equations, Astrophys. J. 131 (1960) 681

  78. [78]

    Amari, C

    T. Amari, C. Boulbe, T. Z. Boulmezaoud, Computing Beltrami fields, SIAM Journal on Scientific Computing 31 (5) (2009) 3217–3254. doi:10.1137/070700942

  79. [79]

    Malhotra, A

    D. Malhotra, A. Cerfon, L.-M. Imbert-G´ erard, et al., Taylor states in stellarators: A fast high- order boundary integral solver, Journal of Computational Physics 397 (2019) 108791. doi:10. 1016/j.jcp.2019.06.067

  80. [80]

    Henry, Geometric Theory of Semilinear Parabolic Equations, Springer, Berlin, 1981

    D. Henry, Geometric Theory of Semilinear Parabolic Equations, Springer, Berlin, 1981

Showing first 80 references.