Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of quasi-periodic solar radio bursts associated with
  propagating fast-mode waves   Radio emission observations from the Learmonth and Bruny Island radio
spectrographs are analysed to determine the nature of a train of discrete,
periodic radio \lq sparks\rq (finite-bandwidth, short-duration isolated radio
features) which precede a type II burst. We analyse extreme ultraviolet (EUV)
imaging from SDO/AIA at multiple wavelengths and identify a series of
quasi-periodic rapidly-propagating enhancements, which we interpret as a fast
wave train, and link these to the detected radio features. The speeds and
positions of the periodic rapidly propagating fast waves and the coronal mass
ejection (CME) were recorded using running-difference images and time-distance
analysis. From the frequency of the radio sparks the local electron density at
the emission location was estimated for each. Using an empirical model for the
scaling of density in the corona, the calculated electron density was used to
obtain the height above the surface at which the emission occurs, and the
propagation velocity of the emission location. The period of the radio sparks,
$\delta t_\mathrm{r}$=1.78$\pm$0.04 min, matches the period of the fast wave
train observed at 171 $\AA$, $\delta t_\mathrm{EUV}$=1.7 $\pm$ 0.2 min. The
inferred speed of the emission location of the radio sparks, 630 km s$^{-1}$,
is comparable to the measured speed of the CME leading edge, 500 km s$^{-1}$,
and the speeds derived from the drifting of the type II lanes. The calculated
height of the radio emission (obtained from the density) matches the observed
location of the CME leading edge. From the above evidence we propose that the
radio sparks are caused by the quasi-periodic fast waves, and the emission is
generated as they catch up and interact with the leading edge of the CME.

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The categories of this paper are: acc-phys
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin
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The categories of this paper are: math