Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A solar tornado observed by AIA/SDO: Rotational flow and evolution of
  magnetic helicity in a prominence and cavity   During 2011/09/24, as observed by the Atmospheric Imaging Assembly (AIA)
instrument of the Solar Dynamic Observatory (SDO) and ground-based \Ha\
telescopes, a prominence and associated cavity appeared above the southwest
limb. On 2011/09/25 8:00UT material flows upwards from the prominence core
along a narrow loop-like structure, accompanied by a rise ($\geq$50,000km) of
the prominence core and the loop. As the loop fades by 10:00, small blobs and
streaks of varying brightness rotate around the top part of the prominence and
cavity, mimicking a cyclone. The most intense and coherent rotation lasts for
over three hours, with emission in both hot ($\sim$1MK) and cold (hydrogen and
helium) lines. We suggest that the cyclonic appearance and overall evolution of
the structure can be interpreted in terms of the expansion of helical
structures into the cavity, and the movement of plasma along helical structures
which appears as a rotation when viewed along the helix axis. The coordinated
movement of material between prominence and cavity suggest that they are
structurally linked. Complexity is great due to the combined effect of these
actions and the line-of-sight integration through the structure which contains
tangled fields.

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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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The categories of this paper are: cond-mat
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph