Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wreathes of Magnetism in Rapidly Rotating Suns   When our Sun was young it rotated much more rapidly than now. Observations of
young, rapidly rotating stars indicate that many possess substantial magnetic
activity and strong axisymmetric magnetic fields. We conduct simulations of
dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical
harmonic (ASH) code to explore the complex coupling between rotation,
convection and magnetism. Here we study dynamo action realized in the bulk of
the convection zone for two systems, rotating at three and five times the
current solar rate. We find that substantial organized global-scale magnetic
fields are achieved by dynamo action in these systems. Striking wreathes of
magnetism are built in the midst of the convection zone, coexisting with the
turbulent convection. This is a great surprise, for many solar dynamo theories
have suggested that a tachocline of penetration and shear at the base of the
convection zone is a crucial ingredient for organized dynamo action, whereas
these simulations do not include such tachoclines. Some dynamos achieved in
these rapidly rotating states build persistent global-scale fields which
maintain amplitude and polarity for thousands of days. In the case at five
times the solar rate, the dynamo can undergo cycles of activity, with fields
varying in strength and even changing polarity. As the magnetic fields wax and
wane in strength, the primary response in the convective flows involves the
axisymmetric differential rotation, which begins to vary on similar time
scales. Bands of relatively fast and slow fluid propagate toward the poles on
time scales of roughly 500 days. In the Sun, similar patterns are observed in
the poleward branch of the torsional oscillations, and these may represent a
response to poleward propagating magnetic field deep below the solar surface.

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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: cs