Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The multi-component field topology of sunspot penumbrae - A diagnostic
  tool for spectropolarimetric measurements   Context: Sunspot penumbrae harbor highly structured magnetic fields and
flows. The moving flux tube model offers an explanation for several observed
phenomena, e.g. the Evershed effect and bright penumbral grains.
  Aims: A wealth of information can be extracted from spectropolarimetric
observations. In order to deduce the structure of the magnetic field in sunspot
penumbrae, detailed forward modeling is necessary. On the one hand, it gives
insight into the sensitivity of various spectral lines to different physical
scenarios. On the other hand, it is a very useful tool to guide inversion
techniques. In this work, we present a generalized 3D geometrical model that
embeds an arbitrarily shaped flux tube in a stratified magnetized atmosphere.
  Methods: The new semi-analytical geometric model serves as a frontend for a
polarized radiative transfer code. The advantage of this model is that it
preserves the discontinuities of the physical parameters across the flux tube
boundaries. This is important for the detailed shape of the emerging Stokes
Profiles and the resulting net circular polarization (NCP).
  Results: (a) The inclination of downflows in the outer penumbra must be
shallower than approximately 15 degrees. (b) Observing the limb-side NCP of
sunspots in the Fe I 1564.8 nm line offers a promising way to identify a
reduced magnetic field strength in flow channels. (c) The choice of the
background atmosphere can significantly influence the shape of the Stokes
profiles, but does not change the global characteristics of the resulting NCP
curves for the tested atmospheric models.

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The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas