Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio Observations of the January 20, 2005 X-Class Event   We present a multi-frequency and multi-instrument study of the 20 January
2005 event. We focus mainly on the complex radio signatures and their
association with the active phenomena taking place: flares, CMEs, particle
acceleration and magnetic restructuring. As a variety of energetic particle
accelerators and sources of radio bursts are present, in the flare-ejecta
combination, we investigate their relative importance in the progress of this
event. The dynamic spectra of {Artemis-IV-Wind/Waves-Hiras with 2000 MHz-20 kHz
frequency coverage, were used to track the evolution of the event from the low
corona to the interplanetary space; these were supplemented with SXR, HXR and
gamma-ray recordings. The observations were compared with the expected radio
signatures and energetic-particle populations envisaged by the {Standard
Flare--CME model and the reconnection outflow termination shock model. A proper
combination of these mechanisms seems to provide an adequate model for the
interpretation of the observational data.

35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
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The categories of this paper are: plasm-ph