Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comment on "Are periodic solar wind number density structures formed in
  the solar corona?" by N. M. Viall et al., 2009, Geophys. Res. Lett., 36,
  L23102, doi:10.1029/2009GL041191   Location of formation of periodic solar wind number density structures is
discussed. Observation of proton and alpha anticorrelation in these structures
[Viall et al., 2009] indicates that taking into account that bulk velocity of
aplha-particles is higher than that of proton the place of formation for these
structures should be located at distance less 0.002 AU from place of
observation.

11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph