Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microwave burst with fine spectral structures in a solar flare on 2011
  August 9   On August 9, 2011, there was an X6.9 flare event occurred near the west limb
of solar disk. From the observation obtained by the spectrometer of the Chinese
Solar Broadband Radio Spectrometer in Huairou (SBRS/Huairou) around the flare,
we find that this powerful flare has only a short-duration microwave burst of
about only 5 minutes, and during the short-duration microwave burst, there are
several kinds of fine structures on the spectrogram. These fine structures
include very short-period pulsations, millisecond spike bursts, and type III
bursts. The most interesting is that almost all of the pulses of very
short-period pulsation (VSP) are structured by clusters of millisecond
timescales of spike bursts or type III bursts. And there exists three different
kinds of frequency drift rates in the VSP: the frequency drift rates with
absolute value of about 55 - 130 MHz s^{-1} in the pulse groups, the frequency
drift rates with absolute value of about 2.91 - 16.9 GHz s^{-1} on each
individual pulse, and the frequency drift rates with absolute value of about 15
- 25 GHz s$^{-1}$) at each individual spike burst or type III burst.

37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn