2008/02/29 by M. Ilgner, Martin Ilgner, Richard P. Nelson +1 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20079307
20 pages, 11 figures, accepted for publication in A&A, high resolution pdf available at http://www.maths.qmul.ac.uk/~rpn/preprints/index.html
arxiv created 2008/02/29 · openalex publication_date 2008/03/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
Context. Protostellar accretion discs have cool, dense midplanes where externally originating ionisation sources such as X-rays or cosmic rays are unable to penetrate. This suggests that for a wide range of radii, MHD turbulence can only be sustained in the surface layers where the ionisation fraction is sufficiently high. A dead zone is expected to exist near the midplane, such that active accretion only occurs near the upper and lower disc surfaces. Recent work, however, suggests that under suitable conditions the dead zone may be enlivened by turbulent transport of ions from the surface layers into the dense interior.