Alfven wave support of a dwarf molecular cloud. I. an isothermal model.

CE Martin, J Heyvaerts, Eric Ronald Priest

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Dwarf (or dark) molecular clouds and molecular clumps have a lifetime which is greater than their dynamical time and must therefore be, in an average sense, in mechanical equilibrium. Equilibrium perpendicular to a global magnetic field is by magnetic forces and it is proposed that along the field the gas is supported by an Alfven wave pressure force. A self-consistent analytical model, utilising a WKB approximation, is developed for such support. It is found that Alfven waves are indeed a good candidate for this support, generating model cloud thicknesses consistent with observations. The effect of damping by the linear process of ion-neutral friction is considered. It is found that the damping of the waves is not a necessary condition for the support of the cloud although weak damping is an advantage. The possible sources of these waves are discussed.

Original languageEnglish
Pages (from-to)1176-1186
Number of pages11
JournalAstronomy & Astrophysics
Volume326
Publication statusPublished - Oct 1997

Keywords

  • ISM: clouds
  • ISM: magnetic fields
  • ISM: structure
  • MHD
  • waves
  • STAR-FORMATION
  • HYDROMAGNETIC-WAVES
  • MAGNETIC-FIELD
  • DARK CLOUD
  • JEANS COLLAPSE
  • DIFFUSION
  • CHEMISTRY
  • RATES
  • GAS

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