Differential Rotation in Solar-Like Stars From Global Simulations

Gómez, Gutiérrez; Smolarkiewicz, Piotr K.; Kosovichev, A. G.; Mansour, N. N.

doi:10.1088/0004-637x/779/2/176

Cited by 118 publications

(166 citation statements)

References 61 publications

Supporting

Mentioning

146

Contrasting

Unclassified

Order By: Relevance

“…As in previous work (Gastine et al 2013(Gastine et al , 2014Guerrero et al 2013a;Käpylä et al 2014), we find two distinct dynamical regimes of DR. One regime is characterized by solar-like DR (DΩ > 0) at low Rossby number (Ro) and the other by anti-solar DR (DΩ < 0) at high Ro, where D = -Ω Ω Ω eq pole is the pole-to-equator rotational contrast. Our transitional value of Ro ∼ 0.16 is lower than that reported in previous studies, but we attribute this to a difference in how Ro is defined.…”

Section: Discussionsupporting

confidence: 86%

“…As the rotation rate of the system decreases, the high-latitude cell extends to lower latitudes, ultimately supplanting the counter cell in the equatorial regions for rotation rates lower than  Ω . The shift from multi-cellular MC profiles in the solar regime to single-celled profiles in the antisolar regime has also been noted by other authors (Guerrero et al 2013a;Gastine et al 2014;Käpylä et al 2014). …”

Section: Identification Of Mean-flow Regimessupporting

confidence: 75%

“…Many of these studies reported a qualitative change in the MC profile in the two regimes (Matt et al 2011;Gastine et al 2013Gastine et al , 2014Guerrero et al 2013a;Käpylä et al 2014). The anti-solar regime (Ro < 1) often exhibits a single circulation cell per hemisphere, with poleward flow in the upper CZ and equatorward flow in the lower CZ.…”

Section: Dynamical Modelsmentioning

confidence: 99%

See 2 more Smart Citations

Meridional Circulation in Solar and Stellar Convection Zones

Featherstone

Miesch

2015

ApJ

152

161

View full text Add to dashboard Cite

We present a series of 3D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic code, that are designed to isolate those processes that drive and shape meridional circulations (MCs) within stellar convection zones. These simulations have been constructed so as to span the transition between solarlike differential rotation (DR; fast equator/slow poles) and "anti-solar" DR (slow equator/fast poles). Solar-like states of DR, which arise when convection is rotationally constrained, are characterized by a very different convective Reynolds stress (RS) than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective RS plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled MC profiles in strong and weak regimes of rotational constraint is linked to a change in the convective RS, which is a clear demonstration of gyroscopic pumping. Latitudinal thermal variations differ between these different regimes, with those in the solar-like regime conspiring to suppress a single cell of MC, whereas the cool poles and warm equator established in the anti-solar states tend to promote single-celled circulations. Although the convective angular momentum transport becomes radially inward at mid-latitudes in anti-solar regimes, it is the MC that is primarily responsible for establishing a rapidly rotating pole. We conclude with a discussion of how these results relate to the Sun, and suggest that the Sun may lie near the transition between rapidly rotating and slowly rotating regimes.

show abstract

Section: Discussionsupporting

confidence: 86%

Section: Identification Of Mean-flow Regimessupporting

confidence: 75%

Section: Dynamical Modelsmentioning

confidence: 99%

See 1 more Smart Citation

Meridional Circulation in Solar and Stellar Convection Zones

Featherstone

Miesch

2015

ApJ

152

161

View full text Add to dashboard Cite

show abstract

“…In particular, Figures 4(b)-(f) show the convective patterns represented in radial velocities that are prevalent during different phases of the cycle (labeled as times t 1 -t 5 in Figure4), with elongated and north-south aligned flows at low latitudes (banana cells) and apparently smaller scales at higher latitudes. Such flows are typical in the rotationally constrained convection captured in global-scale large-eddy MHD simulations (e.g., Miesch et al 2000;Käpylä et al 2011b;Augustson et al 2012Augustson et al , 2013Guerrero et al 2013). In aggregate, the velocity field of those rotationally aligned convective cells produces correlations in the velocity field that yield strong Reynolds stresses (RS) that act to accelerate the equator and slow the poles.…”

Section: Overview Of the Cycling Dynamicsmentioning

confidence: 99%

Grand Minima and Equatorward Propagation in a Cycling Stellar Convective Dynamo

Augustson

Brun

Miesch

et al. 2015

ApJ

113

145

View full text Add to dashboard Cite

The 3D MHD Anelastic Spherical Harmonic 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 timescales, 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 simulation's relatively low magnetic Prandtl number. A mean-field-based analysis of this dynamo simulation demonstrates that it is of the α-Ω type. The timescales that appear to be relevant to the magnetic polarity reversal are also identified.

show abstract

“…Thermal forcing within the convectively unstable layers sustains highly supercritical, turbulent convective fluid motions. The overall simulation design is described in Ghizaru et al (2010), Racine et al (2011), and Guerrero et al (2013). The governing equations are solved using the EULAG-MHD code, the MHD generalization described in of the robust multi-scale flow solver EULAG (Prussa et al 2008).…”

Section: The Simulationmentioning

confidence: 99%

Characteristics of magnetic solar-like cycles in a 3D MHD simulation of solar convection

Passos

Charbonneau

2014

A&A

View full text Add to dashboard Cite

We analyse the statistical properties of the stable magnetic cycle unfolding in an extended 3D magnetohydrodynamic simulation of solar convection produced with the EULAG-MHD code. The millennium simulation spans over 1650 years, in the course of which forty polarity reversals take place on a regular ∼40 yr cadence, remaining well-synchronized across solar hemispheres. In order to characterize this cycle and facilitate its comparison with measures typically used to represent solar activity, we build two proxies for the magnetic field in the simulation mimicking the solar toroidal field and the polar radial field. Several quantities that characterize the cycle are measured (period, amplitudes, etc.) and correlations between them are computed. These are then compared with their observational analogs. From the typical Gnevyshev-Ohl pattern, to hints of Gleissberg modulation, the simulated cycles share many of the characteristics of their observational analogs even though the simulation lacks poloidal field regeneration through active region decay, a mechanism nowadays often considered an essential component of the solar dynamo. Some significant discrepancies are also identified, most notably the in-phase variation of the simulated poloidal and toroidal large-scale magnetic components, and the low degree of hemispheric coupling at the level of hemispheric cycle amplitudes. Possible causes underlying these discrepancies are discussed.

show abstract

Differential Rotation in Solar-Like Stars From Global Simulations

Cited by 118 publications

References 61 publications

Meridional Circulation in Solar and Stellar Convection Zones

Meridional Circulation in Solar and Stellar Convection Zones

Grand Minima and Equatorward Propagation in a Cycling Stellar Convective Dynamo

Characteristics of magnetic solar-like cycles in a 3D MHD simulation of solar convection

Contact Info

Product

Resources

About