Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Protostar Formation in Magnetic Molecular Clouds beyond Ion Detachment:
  II. Typical Axisymmetric Solution   We follow the ambipolar-diffusion--driven formation and evolution of a
fragment in a magnetically supported molecular cloud, until a hydrostatic
protostellar core forms at its center. This problem was formulated in Paper I.
We determine the density, velocity and magnetic field as functions of space and
time, and the contribution of ambipolar diffusion and Ohmic dissipation to the
resolution of the magnetic flux problem of star formation. The issue of whether
the magnetic field ever decouples from the (neutral) matter is also addressed.
We also find that the electrons do not decouple from the field lines before
thermal ionization becomes important and recouples the magnetic field to the
neutral matter. Ohmic dissipation becomes more effective than ambipolar
diffusion as a flux reduction mechanism only at the highest densities (a few
times 10^12 particles per cubic cm). In the high-density central parts of the
core, the magnetic field acquires an almost spatially uniform structure, with a
value that, at the end of the calculation (number density ~ 5 times 10^14
particles per cubic cm), is found to be in excellent agreement with meteoritic
measurements of magnetic fields in the protosolar nebula. Outside the
hydrostatic protostellar core, a concentration of magnetic flux (a "magnetic
wall") forms, which gives rise to a magnetic shock. This magnetic shock is the
precursor of the repeated shocks found by Tassis & Mouschovias (2005) which
cause spasmodic accretion onto the hydrostatic core at later times.

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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
35
The categories of this paper are: mtrl-th