Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revision of Solar Spicule Classification   Solar spicules are the fundamental magnetic structures in the chromosphere
and considered to play a key role in channelling the chromosphere and corona.
Recently, it was suggested by De Pontieu et al. that there were two types of
spicules with very different dynamic properties, which were detected by space-
time plot technique in the Ca ii H line (3968 A) wavelength from Hinode/SOT
observations. 'Type I' spicule, with a 3-7 minute lifetime, undergoes a cycle
of upward and downward motion; in contrast, 'Type II' spicule fades away within
dozens of seconds, without descending phase. We are motivated by the fact that
for a spicule with complicated 3D motion, the space-time plot, which is made
through a slit on a fixed position, could not match the spicule behavior all
the time and might lose its real life story. By revisiting the same data sets,
we identify and trace 105 and 102 spicules in quiet sun (QS) and coronal hole
(CH), respectively, and obtain their statistical dynamic properties. First, we
have not found a single convincing example of 'Type II' spicules. Secondly,
more than 60% of the identified spicules in each region show a complete cycle,
i.e., majority spicules are 'Type I'. Thirdly, the lifetime of spicules in QS
and CH are 148 s and 112 s, respectively, but there is no fundamental lifetime
difference between the spicules in QS and CH reported earlier. Therefore, the
suggestion of coronal heating by 'Type II' spicules should be taken with
cautions. Subject headings: Sun: chromosphere Sun:transition region Sun:corona

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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: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph