Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The quiet Sun's magnetic flux estimated from CaIIH bright inter-granular
  G-band structures   We determine the number density and area contribution of small-scale
inter-granular calcium-II bright G-band structures in images of the quiet Sun
as tracers of kilo-Gauss magnetic flux-concentrations.
  In a 149" x 117" G-band image of the disk center at the activity minimum,
7593 small inter-granular structures ['IGS']were segmented with the
`multiple-level tracking' pattern recognition algorithm ['MLT_4']. The
scatter-plot of the continuum versus the G-band brightness shows the known
magnetic and non-magnetic branches. These branches are largely disentangled by
applying an intrinsic Ca-II excess criterion. The thus obtained 2995 structures
contain 1152 G-band bright points ['BP'] and 1843 G-band faint points ['FP'].
They show a tendency of increasing size with decreasing G-band excess, as
expected from the `hot wall' picture. Their Ca-H and G-band brightness are
slightly related, resembling the known relation of Ca-II and magnetic field
strength. The magnetic flux density of each individual BP and FP is estimated
from their G-band brightness according to MHD-model calculations.
  The entity of BP and FP covers the total field-of-view ['FOV'] with a number
density of 0.32/Mm^2 and a total area contribution of 2.0%. Their individual
calibrations yield a mean flux density of 20 Mx/cm^2 in the entire FOV and 13
Mx/cm^2 for inter-network regions.

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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph