COLLAPSE OF MAGNETIZED SINGULAR ISOTHERMAL TOROIDS. I.THE NONROTATING CASE

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)351-362
Journal / PublicationAstrophysical Journal
Volume599
Publication statusPublished - 10 Dec 2003
Externally publishedYes

Abstract

We study numerically the collapse of nonrotating self-gravitating magnetized singular isothermal toroids characterized by sound speed, a, and level of magnetic to thermal support, H0. In qualitative agreement with treatments by Galli & Shu and other workers, we find that the infalling material is deflected by the field lines toward the equatorial plane, creating a high-density flattened structure, a pseudodisk. The pseudodisk contracts dynamically in the radial direction, dragging the field lines and threading them into a highly pinched configuration that resembles a split monopole. The oppositely directed field lines across the midplane and the large implied stresses may play a role in how magnetic flux is lost in the actual situation in the presence of finite resistivity or ambipolar diffusion. The infall rate into the central regions is given to 5% uncertainty by the formula = (1 + H0)a3/G, where G is the universal gravitational constant, anticipated by semianalytical studies of the self-similar gravitational collapses of the singular isothermal sphere and isopedically magnetized disks. The introduction of finite initial rotation results in a complex interplay between pseudodisk and true (Keplerian) disk formation that is examined in a companion paper.

Research Area(s)

  • accretion, accretion disks, ISM: clouds, MHD, stars: formation

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