Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Element Abundances and Source Plasma Temperatures of Solar Energetic
  Particles   Thirty years ago Breneman and Stone observed that the enhancement or
suppression of element abundances in large solar energetic-particle (SEP)
events varies as a power of the mass-to-charge ratio, A/Q, of the elements.
Since Q during acceleration or transport may depend upon the source plasma
temperature T, the pattern of element enhancements can provide a best-fit
measure of T. The small SEP events we call 3He-rich or "impulsive" show average
enhancements, relative to coronal abundances, rising as the 3.6 power of A/Q to
a factor of ~1000 for (76<=Z<=82)/O and temperature in the range 2-4 MK. This
acceleration is believed to occur in islands of magnetic reconnection on open
field lines in solar flares and jets. It has been recently found that the large
shock-accelerated "gradual" SEP events have a broad range of source plasma
temperatures; 69% have coronal temperatures of T < 1.6 MK, while 24% have T ~ 3
MK, the latter suggesting a seed population containing residual impulsive
suprathermal ions. Most of the large event-to-event abundance variations and
their time variation are largely explained by variations in T magnified by
A/Q-dependent fractionation during transport. However, the non-thermal variance
of impulsive SEP events (~30%) exceeds that of the ~3 MK gradual events (~10%)
so that several small impulsive events must be averaged together with the
ambient plasma to form the seed population for shock acceleration in these
events.

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The categories of this paper are: adap-org
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The categories of this paper are: stat
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int