  The 3-D magnetohydrodynamic (MHD) Anelastic Spherical Harmonic (ASH) code,
using slope-limited diffusion, is employed to capture convective and dynamo
processes achieved in a global-scale stellar convection simulation for a model
solar-mass star rotating at three times the solar rate. The dynamo generated
magnetic fields possesses many time scales, with a prominent polarity cycle
occurring roughly every 6.2 years. The magnetic field forms large-scale
toroidal wreaths, whose formation is tied to the low Rossby number of the
convection in this simulation. The polarity reversals are linked to the
weakened differential rotation and a resistive collapse of the large-scale
magnetic field. An equatorial migration of the magnetic field is seen, which is
due to the strong modulation of the differential rotation rather than a dynamo
wave. A poleward migration of magnetic flux from the equator eventually leads
to the reversal of the polarity of the high-latitude magnetic field. This
simulation also enters an interval with reduced magnetic energy at low
latitudes lasting roughly 16 years (about 2.5 polarity cycles), during which
the polarity cycles are disrupted and after which the dynamo recovers its
regular polarity cycles. An analysis of this grand minimum reveals that it
likely arises through the interplay of symmetric and antisymmetric dynamo
families. This intermittent dynamo state potentially results from the
simulations relatively low magnetic Prandtl number. A mean-field-based analysis
of this dynamo simulation demonstrates that it is of the $\alpha$-$\Omega$
type. The time scales that appear to be relevant to the magnetic polarity
reversal are also identified.
