Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of flux emergence, splitting, merging, and cancellation in
  quiet Sun   We investigate the frequency of magnetic activities, namely flux emergence,
splitting, merging, and cancellation, through an automatic detection in order
to understand the generation of the power-law distribution of magnetic flux
reported by Parnell et al. (2009). The quiet Sun magnetograms observed in the
Na I line by Hinode/ SOT is used in this study. Investigated patches range from
10^{17}Mx to 10^{19}Mx. Emergence and cancellation are much less frequent than
merging and splitting. The time scale for splitting is found to be ~33 minutes
and is independent of the flux contained in the splitting patch. Moreover
magnetic patches split into any flux contents with an equal probability. It is
shown that such a fragmentation process leads to a distribution with a
power-law index -2. Merging has a very weak dependence on flux content only
with a power-law index -0.33. These results suggest that 1) magnetic patches
are fragmented by splitting, merging, and tiny cancellation; 2) flux is removed
from the photosphere through tiny cancellations after these fragmentations.

32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs