Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mean-Field Modeling of $\alpha^2$-Dynamo Coupled with Direct Numerical
  Simulations of Rigidly Rotating Convection   The mechanism of large-scale dynamos in rigidly rotating stratified
convection is explored by direct numerical simulations (DNS) in Cartesian
geometry. A mean-field dynamo model is also constructed using turbulent
velocity profiles consistently extracted from the corresponding DNS results. By
quantitative comparison between the DNS and our mean-field model, it is
demonstrated that the oscillatory $\alpha^2$ dynamo wave, excited and sustained
in the convection zone, is responsible for large-scale magnetic activities such
as cyclic polarity reversal and spatiotemporal migration. The results provide
strong evidence that a nonuniformity of the $\alpha$-effect, which is a natural
outcome of rotating stratified convection, can be an important prerequisite for
large-scale stellar dynamos, even without the $\Omega$-effect.

16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci