Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of Passive Magnetic Field Transport   In recent years, our knowledge of photospheric magnetic fields went through a
thorough transformation--nearly unnoticed by dynamo theorists. It is now
practically certain that the overwhelming majority of the unsigned magnetic
flux crossing the solar surface is in turbulent form (intranetwork and hidden
fields). Furthermore, there are now observational indications (supported by
theoretical arguments discussed in this paper) that the net polarity imbalance
of the turbulent field may give a significant or even dominant contribution to
the weak large-scale background magnetic fields outside unipolar network areas.
This turbulent magnetic field consists of flux tubes with magnetic fluxes below
1e10 Wb (1e18 Mx). The motion of these thin tubes is dominated by the drag of
the surrounding flows, so the transport of this component of the solar magnetic
field must fully be determined by the kinematics of the turbulence (i.e. it is
"passive"), and it can be described by a one-fluid model like mean-field theory
(MFT). This paper reviews the theory of passive magnetic field transport using
mostly first (and occasionally higher) order smoothing formalism; the most
important transport effects are however also independently derived using
Lagrangian analysis for a simple two-component flow model. Solar applications
of the theory are also presented. Among some other novel findings it is
proposed that the observed unsigned magnetic flux density in the photosphere
requires a small-scale dynamo effect operating in the convective zone and that
the net polarity imbalance in turbulent (and, in particular, hidden) fields may
give a major contribution to the weak large-scale background magnetic fields on
the Sun.

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The categories of this paper are: eess
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas