Magnetohydrodynamic motion of a twofluid plasma
Abstract
Here, the twofluid Maxwell system couples frictionless electron and ion fluids via Maxwell’s equations. When the frequencies of light waves, Langmuir waves, and singleparticle cyclotron motion are scaled to be asymptotically large, the twofluid Maxwell system becomes a fastslow dynamical system. This fastslow system admits a formallyexact singlefluid closure that may be computed systematically with any desired order of accuracy through the use of a functional partial differential equation. In the leading order approximation, the closure reproduces magnetohydrodynamics (MHD). Higher order truncations of the closure give an infinite hierarchy of extended MHD models that allow for arbitrary mass ratio, as well as perturbative deviations from charge neutrality. The closure is interpreted geometrically as an invariant slow manifold in the infinitedimensional twofluid phase space, on which twofluid motions are free of highfrequency oscillations. This perspective shows that the full closure inherits a Hamiltonian structure from twofluid theory. By employing infinitedimensional Lie transforms, the Poisson bracket for the allorders closure may be obtained in closed form. Thus, conservative truncations of the singlefluid closure may be obtained by simply truncating the singlefluid Hamiltonian. Moreover, the closedform expression for the allorders bracket gives explicit expressions for a number of the full closure’s conservation laws.more »
 Authors:
 Courant Institute of Mathematical Sciences, New York, NY (United States)
 Publication Date:
 Research Org.:
 Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC24)
 OSTI Identifier:
 1368063
 Alternate Identifier(s):
 OSTI ID: 1372123
 Grant/Contract Number:
 AC0506OR23100
 Resource Type:
 Journal Article: Accepted Manuscript
 Journal Name:
 Physics of Plasmas
 Additional Journal Information:
 Journal Volume: 24; Journal Issue: 8; Journal ID: ISSN 1070664X
 Publisher:
 American Institute of Physics (AIP)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Burby, Joshua W. Magnetohydrodynamic motion of a twofluid plasma. United States: N. p., 2017.
Web. doi:10.1063/1.4994068.
Burby, Joshua W. Magnetohydrodynamic motion of a twofluid plasma. United States. doi:10.1063/1.4994068.
Burby, Joshua W. 2017.
"Magnetohydrodynamic motion of a twofluid plasma". United States.
doi:10.1063/1.4994068.
@article{osti_1368063,
title = {Magnetohydrodynamic motion of a twofluid plasma},
author = {Burby, Joshua W.},
abstractNote = {Here, the twofluid Maxwell system couples frictionless electron and ion fluids via Maxwell’s equations. When the frequencies of light waves, Langmuir waves, and singleparticle cyclotron motion are scaled to be asymptotically large, the twofluid Maxwell system becomes a fastslow dynamical system. This fastslow system admits a formallyexact singlefluid closure that may be computed systematically with any desired order of accuracy through the use of a functional partial differential equation. In the leading order approximation, the closure reproduces magnetohydrodynamics (MHD). Higher order truncations of the closure give an infinite hierarchy of extended MHD models that allow for arbitrary mass ratio, as well as perturbative deviations from charge neutrality. The closure is interpreted geometrically as an invariant slow manifold in the infinitedimensional twofluid phase space, on which twofluid motions are free of highfrequency oscillations. This perspective shows that the full closure inherits a Hamiltonian structure from twofluid theory. By employing infinitedimensional Lie transforms, the Poisson bracket for the allorders closure may be obtained in closed form. Thus, conservative truncations of the singlefluid closure may be obtained by simply truncating the singlefluid Hamiltonian. Moreover, the closedform expression for the allorders bracket gives explicit expressions for a number of the full closure’s conservation laws. Notably, the full closure, as well as any of its Hamiltonian truncations, admits a pair of independent circulation invariants.},
doi = {10.1063/1.4994068},
journal = {Physics of Plasmas},
number = 8,
volume = 24,
place = {United States},
year = 2017,
month = 7
}

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