Ambipolar Diffusion in Interstellar Clouds: One-Dimensional, Isothermal Collapse

The formulation of a theory of star formation faces two fundamental problems: (i) the angular momentum problem, and (ii) the magnetic flux problem. We have previously emonstrated by detailed calculations that magnetic braking by itself can resolve the angular momentum problem (at least for binary stars and, most likely, for single stars as well) during the early, relatively diffuse stages of cloud contraction. The magnetic flux problem lies in the observation that fluxes of typical stars are between 2 and 5 orders of magnitude smaller than fluxes of corresponding masses at interstellar densities. The detailed calculations of collapsing model clouds described in this paper show that the flux-to-mass ratio in cloud cores can decrease by more than 4 orders of magnitude at neutral densities n(,n) < 10('9) cm('-3) due to ambipolar diffusion alone. Ambipolar diffusion sets in at gas densities larger than those by which the bulk of the angular momentum problem is resolved by magnetic braking.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Paleologou, Efthimios

• Physics, Astronomy and Astrophysics

Language dc:language

eng

Identifier

(UMI)AAI8324616

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77355