Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Self-assembly of shallow magnetic spots through strongly stratified
  turbulence   Recent studies have demonstrated that in fully developed turbulence, the
effective magnetic pressure of a large-scale field (non-turbulent plus
turbulent contributions) can become negative. In the presence of strongly
stratified turbulence, this was shown to lead to a large-scale instability that
produces spontaneous magnetic flux concentrations. Furthermore, using a
horizontal magnetic field, elongated flux concentrations with a strength of a
few per cent of the equipartition value were found. Here we show that a uniform
vertical magnetic field leads to circular magnetic spots of equipartition field
strengths. This could represent a minimalistic model of sunspot formation and
highlights the importance of two critical ingredients: turbulence and strong
stratification. Radiation, ionization, and supergranulation may be important
for realistic simulations, but are not critical at the level of a minimalistic
model of magnetic spot formation.

32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an