Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Torsional Alfv\'enic Oscillations Discovered in the Magnetic Free Energy
  During Solar Flares
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph