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Long time convergence of magnetohydrodynamic flows to alfvénic states

Published online by Cambridge University Press:  01 December 2007

MANUEL NÚÑEZ
MANUEL NÚÑEZ*
Affiliation:
Departamento de Análisis Matemático, Universidad de Valladolid, 47005 Valladolid, Spain (mnjmhd@am.uva.es)
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Abstract

Alfvénic states of a plasma, where velocity and magnetic field coincide, form a particular simple class of ideal equilibria and are also found in certain astrophysical phenomena. While transient processes of alignment in turbulent plasmas are well known and due to preferential spectral transfer, the possible long-term evolution of a magnetohydrodynamic plasma towards an alfvénic state has been rarely studied. It is shown that this tendency does not exist: neither specific ideal alfvénic equilibria nor the whole set of such states attract trajectories in any functional sense. Another possibility is that the perturbations of a static equilibrium could tend to become alfvénic, such as the classical Alfvén waves. We find that if these equilibria are current free, when a perturbation approaches an alfvénic state it immediately bounces away from it.

Type
Papers
Information
Journal of Plasma Physics , Volume 73 , Issue 6 , December 2007 , pp. 947 - 955
Copyright
Copyright © Cambridge University Press 2007

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