Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observations of Solar Flare Doppler Shift Oscillations with the Bragg
  Crystal Spectrometer on Yohkoh   Oscillations in solar coronal loops appear to be a common phenomenon.
Transverse and longitudinal oscillations have been observed with both the
Transition Region and Coronal Explorer and Extreme Ultraviolet Imaging
Telescope imaging experiments. Damped Doppler shift oscillations have been
observed in emission lines from ions formed at flare temperatures with the
Solar Ultraviolet Measurements of Emitted Radiation Spectrometer. These
observations provide valuable diagnostic information on coronal conditions and
may help refine our understanding of coronal heating mechanisms. I have
initiated a study of the time dependence of Doppler shifts measured during
flares with the Bragg Crystal Spectrometer (BCS) on Yohkoh. This Letter reports
the detection of oscillatory behavior in Doppler shifts measured as a function
of time in the emission lines of S XV and Ca XIX. For some flares, both lines
exhibit damped Doppler shift oscillations with amplitudes of a few km/s and
periods and decay times of a few minutes. The observations appear to be
consistent with transverse oscillations. Because the BCS observed continuously
for almost an entire solar cycle, it provides numerous flare data sets, which
should permit an excellent characterization of the average properties of the
oscillations.

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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci