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Astrophysics and Space Science

, Volume 292, Issue 1–4, pp 317–323 | Cite as

Star Formation and the Hall Effect

  • Mark Wardle
Article

Abstract

The breakdown of flux-freezing in molecular clouds and protostellar discs is usually approximated by ambipolar diffusion at low densities or by resistive diffusion at high densities. Here an intermediate regime is discussed in which the Hall term in the conductivity tensor is significant, and the vector evolution of the magnetic field, and therefore the evolution of the system under consideration is dramatically altered. Calculations of charged particle abundances in dense gas in molecular clouds and protostellar discs demonstrate that Hall diffusion is important over a surprisingly broad range of conditions.

molecular clouds star formation accretion discs instabilities magnetohydrodynamics 

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References

  1. Balbus, S. A. and Terquem, C.: 2001, ApJ 552, 235.CrossRefADSGoogle Scholar
  2. Gammie, C. F.: 1996, ApJ 457, 355.CrossRefADSGoogle Scholar
  3. Hawley, J. F. and Balbus, S. A.: 1991, ApJ 376, 223.CrossRefADSGoogle Scholar
  4. Igea, J. and Glassgold, A. E.: 1999, ApJ 518, 848.CrossRefADSGoogle Scholar
  5. Nishi, R., Nakano, T. and Umebayashi, T.: 1991, ApJ 368, 181.CrossRefADSGoogle Scholar
  6. Umebayashi, T. and Nakano, T.: 1990, MNRAS 243, 103.ADSGoogle Scholar
  7. Wardle, M. and Salmeron, R.: 2004, Ap&SS 292, 449.Google Scholar
  8. Wardle, M.: 1997, in: D. Wickramasinghe, L. Ferrario and G. Bicknell (eds.), IAU Colloq. 163, Accretion Phenomena and Related Outflows, ASP: San Francisco, p. 561.Google Scholar
  9. Wardle, M.: 1999, MNRAS 307, 849 (W99).CrossRefADSGoogle Scholar
  10. Wardle, M. and Ng, C.: 1999, MNRAS 303, 239.CrossRefADSGoogle Scholar
  11. Weidenschilling, S. J. and Cuzzi, J. N.: 1993, in: E. H. Levy and J. I. Lunine (eds.), Protostars and Planets III, University Arizona Press, Tucson, p. 1031.Google Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Mark Wardle
    • 1
  1. 1.Physics DepartmentMacquarie UniversityNSWAustralia

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