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Title:The role of ambipolar diffusion in the formation of interstellar cloud cores and protostars
Author(s):Morton, Scott Allyn
Doctoral Committee Chair(s):Mouschovias, T. Ch.
Department / Program:Physics
Discipline:Physics
Degree:Ph.D.
Genre:Dissertation
Subject(s):ambipolar diffusion
interstellar cloud cores
protostars
formation of stars
astrophysics
Abstract:The formation of stars is a fundamental unsolved problem in astrophysics. Interstellar molecular clouds, observed to be the birth place of stars, have masses much larger than those of typical stars. Observed densities, temperatures, and strengths of well-ordered magnetic fields imply that magnetic forces, transmitted to the neutral fluid through collisions with ions, dominate thermal forces in supporting these objects against self-gravity. The anisotropy of the Lorentz force, which is always perpendicular to the magnetic field, allows a simplified treatment of the dynamics involving motion along the magnetic field. We derive a reduced system of non-linear, non-ideal magnetohydrodynamic equations by assuming a balance of thermal and gravitational forces along the magnetic field. We then study both the stability of dense clouds as well as their non-linear evolution/ contraction owing to ambipolar diffusion. An important result is the selection by ambipolar diffusion of a characteristic mass comparable to a solar mass.
Issue Date:1991
Genre:Dissertation / Thesis
Type:Text
Language:English
URI:http://hdl.handle.net/2142/18891
Rights Information:1991 Scott Allyn Morton
Date Available in IDEALS:2011-04-27
Identifier in Online Catalog:3471936


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