Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydromagnetic instabilities in protoneutron stars   The stability properties of newly born neutron stars, or proto--neutron
stars, are considered. We take into account dissipative processes, such as
neutrino transport and viscosity, in the presence of a magnetic field. In order
to find the regions of the star subject to different sorts of instability, we
derive the general instability criteria and apply it to evolutionary models of
PNSs. The influence of the magnetic field on instabilities is analyzed and the
critical magnetic field stabilizing the star is obtained. In the light of our
results, we estimate of the maximum poloidal magnetic field that might be
present in young pulsars or magnetars.

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The categories of this paper are: cs
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
16
The categories of this paper are: stat
18
The categories of this paper are: econ