Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Un-interrupted Sun-as-a-star Helioseismic Observations over Multiple
  Solar Cycles   We analyze Sun-as-a-star observations spanning over solar cycles 22 -- 24
from the ground-based network BiSON and solar cycles 23 -- 24 collected by the
space-based VIRGO and GOLF instruments on board the {\it SoHO} satellite. Using
simultaneous observations from all three instruments, our analysis suggests
that the structural and magnetic changes responsible for modifying the
frequencies remained comparable between cycle 23 and cycle 24 but differ from
cycle 22. Thus we infer that the magnetic layer of the Sun has become thinner
since the beginning of cycle 23 and continues during the current cycle.

23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat