Turbulent diffusion of large-scale magnetic fields in the presence of ambipolar drift

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Abstract

The decay of a large-scale magnetic field embedded in a weakly ionized fluid is studied in two-dimensional geometry. We consider cases where the magnetic energy density is less than the total kinetic energy density. Using both quasi-linear analysis and numerical simulations, we show that when the motions of the neutrals are turbulent, the effective diffusivity of a large-scale magnetic field depends on both the magnetic field strength and the frictional coupling constant between ions and neutrals. The effective diffusivity is comparable to the turbulent rate if the magnetic field is weak enough and if the frictional coupling is strong enough. However, for values of the parameters typical of the interstellar medium, we show that turbulent diffusion is bound to be reduced.

Original languageEnglish
Pages (from-to)183-195
Number of pages13
JournalAstrophysical Journal
Volume477
Issue number1
DOIs
Publication statusPublished - 1 Jan 1997
Externally publishedYes

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turbulent diffusion
magnetic field
magnetic fields
diffusivity
flux density
kinetic energy
field strength
geometry
fluid
ion
fluids
decay
simulation
energy
ions

Bibliographical note

Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.

Keywords

  • Diffusion
  • ISM: magnetic field
  • MHD
  • Turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Turbulent diffusion of large-scale magnetic fields in the presence of ambipolar drift. / Kim, Eun Jin.

In: Astrophysical Journal, Vol. 477, No. 1 , 01.01.1997, p. 183-195.

Research output: Contribution to journalArticle

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