Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Helioseismic and Magnetic Imager observations of linear polarization
  from a loop prominence system   White-light observations by the Solar Dynamics Observatory's Helioseismic and
Magnetic Imager of a loop-prominence system occurring in the aftermath of an
X-class flare on 2013 May 13 near the eastern solar limb show a linearly
polarized component, reaching up to $\sim$20% at an altitude of $\sim$33 Mm,
about the maximal amount expected if the emission were due solely to Thomson
scattering of photospheric light by the coronal material. The mass associated
with the polarized component was 8.2$\times$10$^{14}$ g. At 15 Mm altitude, the
brightest part of the loop was 3(+/-0.5)% linearly polarized, only about 20% of
that expected from pure Thomson scattering, indicating the presence of an
additional unpolarized component at wavelengths near Fe I (617.33 nm), probably
thermal emission. We estimated the free electron density of the white-light
loop system to possibly be as high as 1.8$\times$10$^{12}$ cm$^{-3}$.

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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
1
The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int