2003/07/04 by M. Wardle, Mark Wardle · 2 citations
Physics and Astronomy · #Advanced Chemical Physics Studies #Astrophysics and Star Formation Studies #Atomic and Molecular Physics #astro-ph
paper · pdf · doi:10.1023/b:astr.0000045033.80068.1f
published as Astrophys.Space Sci.292:317-323,2004 · 8 pages, 5 figures, Latex, kluwer.cls. To appear in the proceedings of "Magnetic fields and star formation: theory versus observations", Madrid, April 21-25 2003
arxiv created 2003/07/04 · openalex publication_date 2004/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
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 I discuss an intermediate regime 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.