Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Numerical sunspot models: Robustness of photospheric velocity and
  magnetic field structure   MHD simulations of sunspots have successfully reproduced many aspects of
sunspot fine structure as consequence of magneto convection in inclined
magnetic field. We study how global sunspot properties and penumbral fine
structure depend on the magnetic top boundary condition as well as on grid
spacing. The overall radial extent of the penumbra is subject to the magnetic
top boundary condition. All other aspects of sunspot structure and penumbral
fine structure are resolved at an acceptable level starting from a grid
resolution of 48 [24] km (horizontal [vertical]). We find that the amount of
inverse polarity flux and the overall amount of overturning convective motions
in the penumbra are robust with regard to both, resolution and boundary
conditions. At photospheric levels Evershed flow channels are strongly
magnetized. We discuss in detail the relation between velocity and magnetic
field structure in the photosphere and point out observational consequences.

28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
16
The categories of this paper are: stat