Magnetic diffusion and the motion of field lines

A. L. Wilmot-Smith, E. R. Priest, G. Hornig

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    27 Citations (Scopus)


    Diffusion of a magnetic field through a plasma is discussed in one-, two- and three-dimensional configurations, together with the possibility of describing such diffusion in terms of a magnetic flux velocity, which, when it exists, is in general non-unique. Physically useful definitions of such a velocity include doing so in terms of the energy flow or in such a way that it vanishes in a steady state. Straight field lines (or plane flux surfaces) diffuse as if flux is disappearing at a neutral sheet, whereas circular field lines (or cylindrical flux surfaces) do so as if flux is disappearing at an 0-type neutral line. In three dimensions it is not always possible to define a flux velocity, for example when the magnetic flux through a closed field line is changing in time. However, in at least some such cases it is possible to describe the behaviour of the magnetic field in terms of a pair of quasi-flux-velocities.
    Original languageEnglish
    Pages (from-to)177-197
    Number of pages21
    JournalGeophysical & Astrophysical Fluid Dynamics
    Issue number2
    Publication statusPublished - 2005


    • Magnetohydrodynamics (MHD)
    • Magnetic diffusion
    • Plasmas
    • MHD


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