Dynamo Models for Planets Other Than Earth

Stanley, Sabine; Glatzmaier, Gary A.

doi:10.1007/s11214-009-9573-y

Cited by 85 publications

(35 citation statements)

References 136 publications

(162 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Comparison with threedimensional numerical simulations verifies and inspires theoretical models (Moll et al 2011;Schrinner et al 2005Schrinner et al , 2007Wilkin et al 2007;Harder & Hansen 2005;Stanley & Glatzmaier 2010;Tobias et al 2011). This work reports on a resilient and newly identified feature of characteristic dynamo action in three-dimensional, convectively driven, homogeneously turbulent, Boussinesq magnetoconvection based on pseudospectral direct numerical simulations using the magnetohydrodynamic (MHD) fluid approximation (Chandrasekhar 1961).…”

Section: Introductionsupporting

confidence: 62%

Fluctuation dynamo amplified by intermittent shear bursts in convectively driven magnetohydrodynamic turbulence

Pratt

Busse

Müller

2013

A&A

View full text Add to dashboard Cite

Intermittent large-scale high-shear flows are found to occur frequently and spontaneously in direct numerical simulations of statistically stationary turbulent Boussinesq magnetohydrodynamic (MHD) convection. The energetic steady state of the system is sustained by convective driving of the velocity field and small-scale dynamo action. The intermittent emergence of flow structures with strong velocity and magnetic shearing generates magnetic energy at an elevated rate on time scales that are longer than the characteristic time of the large-scale convective motion. The resilience of magnetic energy amplification suggests that intermittent shear bursts are a significant driver of dynamo action in turbulent magnetoconvection.

show abstract

Section: Introductionsupporting

confidence: 62%

Fluctuation dynamo amplified by intermittent shear bursts in convectively driven magnetohydrodynamic turbulence

Pratt

Busse

Müller

2013

A&A

View full text Add to dashboard Cite

show abstract

“…(A color version of this figure is available in the online journal.) (see, e.g., Stanley & Glatzmaier 2009, for a review of dynamo modeling).…”

Section: Discussionmentioning

confidence: 99%

Self-Consistent Model Atmospheres and the Cooling of the Solar System's Giant Planets

Fortney¹,

Ikoma²,

Nettelmann³

et al. 2011

ApJ

142

149

View full text Add to dashboard Cite

We compute grids of radiative-convective model atmospheres for Jupiter, Saturn, Uranus, and Neptune over a range of intrinsic fluxes and surface gravities. The atmosphere grids serve as an upper boundary condition for models of the thermal evolution of the planets. Unlike previous work, we customize these grids for the specific properties of each planet, including the appropriate chemical abundances and incident fluxes as a function of solar system age. Using these grids, we compute new models of the thermal evolution of the major planets in an attempt to match their measured luminosities at their known ages. Compared to previous work, we find longer cooling times, predominantly due to higher atmospheric opacity at young ages. For all planets, we employ simple "standard" cooling models that feature adiabatic temperature gradients in the interior H/He and water layers, and an initially hot starting point for the calculation of subsequent cooling. For Jupiter, we find a model cooling age ∼10% longer than previous work, a modest quantitative difference. This may indicate that the hydrogen equation of state used here overestimates the temperatures in the deep interior of the planet. For Saturn, we find a model cooling age ∼20% longer than previous work. However, an additional energy source, such as that due to helium phase separation, is still clearly needed. For Neptune, unlike in work from the 1980s and 1990s, we match the measured T eff of the planet with a model that also matches the planet's current gravity field constraints. This is predominantly due to advances in the high-pressure equation of state of water. This may indicate that the planet possesses no barriers to efficient convection in its deep interior. However, for Uranus, our models exacerbate the well-known problem that Uranus is far cooler than calculations predict, which could imply strong barriers to interior convective cooling. The atmosphere grids are published here as tables, so that they may be used by the wider community.

show abstract

“…These systems may operate in very different regimes and the presence of the magnetic fields may affect the dynamics in subtly different ways. For example for rapidly rotating planetary dynamos (see, e.g., Roberts & Glatzmaier 2000;Stellmach & Hansen 2004;Kuang et al 2008;Stanley & Glatzmaier 2010) the presence of the magnetic field allows the breaking of the Taylor-Proudman constraint and so can lead to efficient convection and dynamo action on the strong-field solution branch (Childress & Soward 1972). In conditions with strong shears such as accretion disk dynamos, the presence of a finite amplitude magnetic field can lead to the possibility of joint (magnetorotational) instabilities and the presence of steady and oscillatory nonlinear dynamo solutions near onset.…”

Section: Introductionmentioning

confidence: 99%

On the Generation of Organized Magnetic Fields

Tobias

Cattaneo

Brummell

2011

ApJ

View full text Add to dashboard Cite

Motivated by the problem of the origin of astrophysical magnetic fields, we introduce two concepts. The first is that of a "system-scale dynamo", i.e., a dynamo that can organize magnetic fields on the scale of the astrophysical object. The second is that of an "essentially nonlinear dynamo". This is a dynamo which relies on a velocity driven by magnetic forces and/or magnetic instabilities. We construct a simple framework that can be used to study such dynamos and give examples in which the evolution is such to generate a system-scale field. We argue that this framework provides a valuable complementary approach to the more conventional studies based on kinematic mean-field dynamo theory.

show abstract

Dynamo Models for Planets Other Than Earth

Cited by 85 publications

References 136 publications

Fluctuation dynamo amplified by intermittent shear bursts in convectively driven magnetohydrodynamic turbulence

Fluctuation dynamo amplified by intermittent shear bursts in convectively driven magnetohydrodynamic turbulence

Self-Consistent Model Atmospheres and the Cooling of the Solar System's Giant Planets

On the Generation of Organized Magnetic Fields

Contact Info

Product

Resources

About