Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Features of Microwave Radiation and Magnetographic Characteristics of
  Solar Active Region NOAA 12242 Before the X1.8 Flare on December 20, 2014   This paper continues the cycle of authors' works on the detection of
precursors of large flares (M5 and higher classes) in active regions (ARs) of
the Sun by their microwave radiation and magnetographic characteristics.
Generalization of the detected precursors of strong flares can be used to
develop methods for their prediction. This paper presents an analysis of the
development of NOAA AR 12242, in which an X1.8 flare occurred on December 20,
2014. The analysis is based on regular multiazimuth and multiwavelength
observations with the RATAN-600 radio telescope in the range 1.65-10 cm with
intensity and circular polarization analysis and data from the Solar Dynamics
Observatory (SDO). It was found that a new component appeared in the AR
microwave radiation two days before the X-flare. It became dominant in the AR
the day before the flare and significantly decreased after the flare. The use
of multiazimuth observations from RATAN-600 and observations at 1.76 cm from
the Nobeyama Radioheliograph made it possible to identify the radio source that
appeared before the X-flare with the site of the closest convergence of
opposite polarity fields near the neutral line in the AR. It was established
that the X-flare occurred 20 h after the total gradient of the magnetic field
of the entire region calculated from SDO/HMI data reached its maximum value.
Analysis of the evolution of the microwave source that appeared before the
X-flare in AR 12242 and comparison of its parameters with the parameters of
other components of the AR microwave radiation showed that the new source can
be classified as neutral line associated source (NLS), which were repeatedly
detected by the RATAN-600 and other radio telescopes 1-3 days before the large
flares.

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The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
2
The categories of this paper are: math