Ab Initio Simulations for Material Properties Along the Jupiter Adiabat

French, Martin; Becker, Andreas; Lorenzen, Winfried; Nettelmann, Nadine; Bethkenhagen, Mandy; Wicht, Johannes; Redmer, R.

doi:10.1088/0067-0049/202/1/5

Cited by 222 publications

(326 citation statements)

References 91 publications

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“…If as in Stevenson & Salpeter (1977) we assume turbulent flow over the scale of a droplet (Re ≡ vd/ν 10 3 ), then C = 0.5 (Landau & Lifshitz 1959) and we arrive at a smaller minimum size d min ≈ 10 −2 cm; the discrepancy may be the result of a dimensional error in the earlier calculation. However, given a typical kinematic viscosity ν = 4 × 10 −3 cm 2 s −1 (French et al 2012), the Reynolds number Re ≡ ud/ν ≈ 25 so that a turbulent drag force is not appropriate. If instead we balance buoyancy with a Stokes drag appropriate for low Reynolds number, then (Landau & Lifshitz 1959) …”

Section: Hydrogen-helium Phase Separationmentioning

confidence: 99%

“…In Figure 2 we show values of Pr, τ , and R crit , derived from the ab initio transport properties obtained by French et al (2012) for a Jupiter adiabat. Here the calculation of τ (and thus R crit ) assumes an effective composition diffusivity κ µ that is of order the He-He self-diffusion coefficient reported in that paper.…”

Section: A Parametric Model For Double-diffusive Convectionmentioning

confidence: 99%

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Bayesian Evolution Models for Jupiter With Helium Rain and Double-Diffusive Convection

Mankovich

Fortney

Moore

2016

ApJ

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Hydrogen and helium demix when sufficiently cool, and this bears on the evolution of all giant planets at large separations at or below roughly a Jupiter mass. We model the thermal evolution of Jupiter, including its evolving helium distribution following results of ab initio simulations for helium immiscibility in metallic hydrogen. After 4 Gyr of homogeneous evolution, differentiation establishes a thin helium gradient below 1 Mbar that dynamically stabilizes the fluid to convection. The region undergoes overstable double-diffusive convection (ODDC), whose weak heat transport maintains a superadiabatic temperature gradient. With a generic parameterization for the ODDC efficiency, the models can reconcile Jupiter's intrinsix flux, atmospheric helium content, and radius at the age of the solar system if the Lorenzen et al. H-He phase diagram is translated to lower temperatures. We cast the evolutionary models in an MCMC framework to explore tens of thousands of evolutionary sequences, retrieving probability distributions for the total heavy element mass, the superadiabaticity of the temperature gradient due to ODDC, and the phase diagram perturbation. The adopted SCvH-I equation of state favors inefficient ODDC such that a thermal boundary layer is formed, allowing the molecular envelope to cool rapidly while the deeper interior actually heats up over time. If the overall cooling time is modulated with an additional free parameter to imitate the effect of a colder or warmer EOS, the models favor those that are colder than SCvH-I. In this case the superadiabaticity is modest and a warming or cooling deep interior are equally likely. Subject headings: planets and satellites: physical evolution -planets and satellites: interiors -planets and satellites: individual (Jupiter) -methods: statistical 1. INTRODUCTION Cool giant planets are relics of the protoplanetary systems from which they formed in the sense that they do not fuse protons, and they are well-bound enough that even hydrogen does not escape appreciably over tens of billions of years. Their thermal evolution is thus relatively simple, and understanding it empowers us to use the present states of giant planets to learn about their history and formation. The open questions about planet formation thus motivate a comprehensive theory of giant planet evolution, which will continue to be driven heavily by our own, well-studied giant planets, Jupiter and Saturn.A Henyey-type stellar evolution calculation for a Jupitermass object was first performed by Graboske et al. (1975), who showed that a convective, homogeneous sphere of fluid hydrogen and helium could cool to Jupiter's observed luminosity over roughly the right timescale, and noted that among all model inputs, the equation of state (EOS) and superadiabaticity of the temperature gradient have the strongest influence on the overall cooling time.These two fundamental physical inputs are closely related. The EOS (paired with a hydrostatic model) is necessary to translate the planet's tangible properties...

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Section: Hydrogen-helium Phase Separationmentioning

confidence: 99%

Section: A Parametric Model For Double-diffusive Convectionmentioning

confidence: 99%

Bayesian Evolution Models for Jupiter With Helium Rain and Double-Diffusive Convection

Mankovich

Fortney

Moore

2016

ApJ

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“…2 The electrical conductivity in Jupiter's interior has also been calculated using ab initio simulations (French et al 2012). Above 0.94R J , it agrees well with the calculation based on the semiconductor model with linear band gaps.…”

Section: B Rayleigh Drag and Subgrid-scale Dissipationmentioning

confidence: 99%

Scaling of Off-Equatorial Jets in Giant Planet Atmospheres

Liu

Schneider

2015

Journal of the Atmospheric Sciences

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In the off-equatorial region of Jupiter's and Saturn's atmospheres, baroclinic eddies transport angular momentum out of retrograde and into prograde jets. In a statistically steady state, this angular momentum transfer by eddies must be balanced by dissipation, likely produced by magnetohydrodynamic (MHD) drag in the planetary interior. This paper examines systematically how an idealized representation of this drag in a general circulation model (GCM) of the upper atmosphere of giant planets modifies jet characteristics, the angular momentum budget, and the energy budget.In the GCM, Rayleigh drag at an artificial lower boundary (with mean pressure of 3 bar) is used as a simple representation of the MHD drag that the flow on giant planets experiences at depth. As the drag coefficient decreases, the eddy length scale and eddy kinetic energy increase, as they do in studies of two-dimensional turbulence. Off-equatorial jets become wider and stronger, with increased interjet spacing. Coherent vortices also become more prevalent. Generally, the jet width scales with the Rhines scale, which is of similar magnitude as the Rossby radius in the simulations. The jet strength increases primarily through strengthening of the barotropic component, which increases as the drag coefficient decreases because the overall kinetic energy dissipation remains roughly constant. The overall kinetic energy dissipation remains roughly constant presumably because it is controlled by baroclinic conversion of potential to kinetic energy in the upper troposphere, which is mainly determined by the differential solar radiation and is only weakly dependent on bottom drag and barotropic flow variations.For Jupiter and Saturn, these results suggest that the wider and stronger jets on Saturn may arise because the MHD drag on Saturn is weaker than on Jupiter, while the thermodynamic efficiencies of the atmospheres are not sensitive to the drag parameters.

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“…This state challenges many-particle theory since strong ionion correlations and partially degenerate electrons prohibit simplified treatments, e.g., by using perturbation theory. Furthermore, WDM is relevant for astrophysics, e.g., for interior, evolution, and dynamo models of giant planets [1][2][3], and for inertial confinement fusion research [4,5]. The dynamic structure factor (DSF), the spectral function of the density-density correlations in the system, is of fundamental importance for theoretical models of WDM and is needed to determine equation of states (EOS) and the transport properties.…”

Section: Introductionmentioning

confidence: 99%

Ab initiosimulations of the dynamic ion structure factor of warm dense lithium

et al. 2017

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We present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible target inhomogeneities on x-ray scattering spectra.

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Ab Initio Simulations for Material Properties Along the Jupiter Adiabat

Cited by 222 publications

References 91 publications

Bayesian Evolution Models for Jupiter With Helium Rain and Double-Diffusive Convection

Bayesian Evolution Models for Jupiter With Helium Rain and Double-Diffusive Convection

Scaling of Off-Equatorial Jets in Giant Planet Atmospheres

Ab initiosimulations of the dynamic ion structure factor of warm dense lithium

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