Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new type of small-scale downflow patches in sunspot penumbrae   A sunspot penumbra is observationally examined to reveal properties of
small-scale flow structures and how they are related to the filamentary
magnetic structures and the Evershed flow. We also study how the photospheric
dynamics is related to chromospheric activities. The study is based on data
analysis of spectro-polarimetric observations of photospheric Fe I lines with
the Solar Optical Telescope aboard Hinode in a sunspot penumbra at different
heliocentric angles. Vector magnetic fields and velocities are derived using
the spectro-polarimetric data and a Stokes inversion technique. An observation
with a Ca II H filtergram co-spatial and co-temporal with the
spectro-polarimetric one is also used to study possible chromospheric
responses. We find small patches with downflows at photospheric layers. The
downflow patches have a size of 0.5" or smaller and have a geometrical
configuration different from that of the Evershed flow. The downflow velocity
is about 1 km/s at lower photspheric layers, and is almost zero in the upper
layers. Some of the downflow patches are associated with brightenings seen in
Ca II H images. The downflows are possible observational signatures of downward
flows driven by magnetic reconnection in the interlaced magnetic field
configuration, where upward flows make brightenings in the chromosphere.
Another possibility is that they are concentrated downward flows of overturning
magnetoconvection.

22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess