A5023169746- High-pressure geophysics and materials
- Astro and Planetary Science
- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Stellar, planetary, and galactic studies
- Planetary Science and Exploration
- Methane Hydrates and Related Phenomena
- Geological and Geochemical Analysis
- Geomagnetism and Paleomagnetism Studies
- Atomic and Molecular Physics
- Scientific Research and Discoveries
- Spacecraft and Cryogenic Technologies
- Astrophysics and Star Formation Studies
- Space Exploration and Technology
- Inorganic Fluorides and Related Compounds
- Geology and Paleoclimatology Research
- earthquake and tectonic studies
- Physics of Superconductivity and Magnetism
- Phase Equilibria and Thermodynamics
- Gas Dynamics and Kinetic Theory
- Catalysis and Oxidation Reactions
- Energetic Materials and Combustion
- Nuclear Physics and Applications
- Diamond and Carbon-based Materials Research
- Chemical Thermodynamics and Molecular Structure
University of California, Berkeley
2015-2024
Planetary Science Institute
2015-2024
Berkeley College
2008-2022
Miller College
2013
Carnegie Institution for Science
2004-2010
Geophysical Laboratory
2004-2010
University of California System
2008
Los Alamos National Laboratory
2007
University of Arizona
2007
Lawrence Livermore National Laboratory
2001-2004
We use new interior models of cold planets to investigate the mass-radius relationships solid exoplanets, considering made primarily iron, silicates, water, and carbon compounds. find that for terrestrial mass all compositions we considered follow a generic functional form is not simple power law: log10 Rs = k1 + log10(Ms) - k2M up Mp ≈ 20 M⊕, where Ms are scaled radius values. This arises because common building blocks have equations state well approximated by modified polytrope ρ ρ0 cPn....
The Juno spacecraft has measured Jupiter's low-order, even gravitational moments, $J_2$--$J_8$, to an unprecedented precision, providing important constraints on the density profile and core mass of planet. Here we report a selection interior models based ab initio computer simulations hydrogen-helium mixtures. We demonstrate that dilute core, expanded significant fraction planet's radius, is helpful in reconciling calculated $J_n$ with Juno's observations. Although model predictions are...
The interior structure of Saturn, the depth its winds, and mass age rings constrain formation evolution. In final phase Cassini mission, spacecraft dived between planet innermost ring, at altitudes 2600 to 3900 kilometers above cloud tops. During six these crossings, a radio link with Earth was monitored determine gravitational field rings. We find that Saturn's gravity deviates from theoretical expectations requires differential rotation atmosphere extending least 9000 kilometers. total is...
Restricted path integral Monte Carlo simulations have been used to calculate the equilibrium properties of deuterium for two densities: $0.674$ and $0.838\mathrm{g}{\mathrm{cm}}^{\ensuremath{-}3}$ ( ${r}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.00$ 1.86) in temperature range ${10}^{5}\ensuremath{\le}T\ensuremath{\le}{10}^{6}\mathrm{K}$. We carefully assess size effects dependence on time step integral. Further, we compare results obtained with a free particle nodal restriction...
Equilibrium properties of hydrogen-helium mixtures under conditions similar to the interior giant gas planets are studied by means first principle density functional molecular dynamics simulations. We investigate and atomic fluid phase hydrogen with without presence helium for densities between $\rho=0.19$ g$ $cm$^{-3}$ $\rho=0.66$ temperatures from $T=500 $K $T=8000 {K}$. Helium has a crucial influence on ionic electronic structure liquid. Hydrogen molecule bonds shortened as well...
Understanding and designing inertial confinement fusion (ICF) implosions through radiation-hydrodynamics simulations relies on the accurate knowledge of equation state (EOS) deuterium tritium fuels. To minimize drive energy for ignition, imploding shell DT fuel must be kept as cold possible. Such low-adiabat ICF can access to coupled degenerate plasma conditions, in which analytical EOS models become inaccurate due many-body effects. Using path-integral Monte Carlo (PIMC) we have derived a...
Hydrogen-helium mixtures at conditions of Jupiter's interior are studied with first-principles computer simulations. The resulting equation state (EOS) implies that Jupiter possesses a central core 14-18 Earth masses heavier elements, result supports accretion as the standard model for formation hydrogen-rich giant planets. Our nominal has about 4 planetary ices in H-He-rich mantle, is, within modeling uncertainty 6 masses, consistent abundances measured by 1995 Galileo entry probe mission,...
Accurate knowledge about the equation of state (EOS) deuterium is critical to inertial confinement fusion (ICF). Low-adiabat ICF implosions routinely access strongly coupled and degenerate plasma conditions. Using path integral Monte Carlo method, we have derived a first-principles EOS (FPEOS) table deuterium. It first ab initio which completely covers typical implosion trajectory in density temperature ranges ρ=0.002-1596 g/cm3 T=1.35 eV-5.5 keV. Discrepancies internal energy pressure been...
We present a 5-phase equation of state (EOS) for elemental carbon. The phases considered are: diamond, BC8, simple-cubic, simple-hexagonal, and the liquid/plasma state. solid phase free energies are constrained by density functional theory (DFT) calculations. Vibrational contributions to energy each treated within quasiharmonic framework. liquid model is fitting combination DFT molecular dynamics performed over range 10,000 K < T 100,000 K, path integral quantum Monte Carlo calculations >...
Using density functional molecular dynamics simulations, we determine the equation of state (EOS) for hydrogen–helium mixtures spanning density–temperature conditions typical giant-planet interiors, ∼0.2–9 g cm−3 and 1000–80,000 K a helium mass fraction 0.245. In addition to computing internal energy pressure, entropy using an ab initio thermodynamic integration technique. A comprehensive EOS table with 391 points is constructed results are presented in form two-dimensional free fit...
Using ab initio simulations we investigate whether water ice is stable in the cores of giant planets, or it dissolves into layer metallic hydrogen above. By Gibbs free energy calculations find that for pressures between 10 and 40 Mbar ice-hydrogen interface thermodynamically unstable at temperatures above approximately 3000 K, far below temperature core-mantle boundaries Jupiter Saturn. This implies dissolution core material fluid layers planets favored, further modeling extent erosion warranted.
We develop an all-electron path integral Monte Carlo method with free-particle nodes for warm dense matter and apply it to water carbon plasmas. thereby extend studies beyond hydrogen helium elements core electrons. Path results pressures, internal energies, pair-correlation functions compare well density functional theory molecular dynamics calculations at temperatures of (2.5-7.5)×10(5) K, both methods together form a coherent equation state over density-temperature range 3-12 g/cm(3)...
Gas giants are believed to form by the accretion of hydrogen-helium gas around an initial protocore rock and ice. The question whether rocky parts core dissolve into fluid H-He layers following formation has significant implications for planetary structure evolution. Here we use ab initio calculations study solubility in hydrogen, choosing MgO as a representative example materials, find be highly soluble H temperatures excess approximately 10000 K, implying redistribution material Jupiter...
ABSTRACT In anticipation of new observational results for Jupiter's axial moment inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number preliminary Jupiter interior models. We combine ab initio computer simulations hydrogen–helium mixtures, including immiscibility calculations, with nonperturbative calculation coefficients, to derive self-consistent model planet's external gravity inertia. assume helium rain modified temperature...
Using density functional molecular dynamics free energy calculations, we show that the body-centered-cubic phase of superionic ice previously believed to be only is in fact thermodynamically unstable compared a novel with oxygen positions fcc lattice sites. The has lower proton mobility than bc and may exhibit higher melting temperature. We predict transition between two phases at pressure 1 +/- 0.5 Mbar, potential consequences for interiors giants such as Uranus Neptune.
This article provides an overview of how models giant planet interiors are constructed. We review measurements from past space missions that provide constraints for the interior structure Jupiter. discuss typical three-layer consist a dense central core and inner metallic outer molecular hydrogen-helium layer. These rely heavily on experiments, analytical theory, first-principle computer simulations hydrogen helium to understand their behavior up extreme pressures ~10 Mbar temperatures...
We put together a first-principles equation of state (FPEOS) database for matter at extreme conditions by combining results from path integral Monte Carlo and density functional molecular dynamics simulations the elements H, He, B, C, N, O, Ne, Na, Mg, Al, Si as well compounds $\mathrm{LiF}, {\mathrm{B}}_{4}\mathrm{C}, \mathrm{BN}, {\mathrm{CH}}_{4}, {\mathrm{CH}}_{2}, {\mathrm{C}}_{2}{\mathrm{H}}_{3}, \mathrm{CH}, {\mathrm{C}}_{2}\mathrm{H}, \mathrm{MgO}, \mathrm{and} {\mathrm{MgSiO}}_{3}$....
While Jupiter's massive gas envelope consists mainly of hydrogen and helium, the key to understanding formation evolution lies in distribution remaining (heavy) elements. Before Juno mission, lack high-precision gravity harmonics precluded use statistical analyses a robust determination heavy-elements envelope. In this paper, we assemble most comprehensive diverse collection Jupiter interior models date it study heavy elements planet's We apply Bayesian approach our model calculations,...
The Juno mission has revolutionized and challenged our understanding of Jupiter. As transitioned to its extended mission, we review the major findings Jupiter's internal structure relevant formation evolution. Results from Juno's investigation interior imply that planet compositional gradients is accordingly non-adiabatic, with a complex structure. These new results current models evolution require revision. In this paper, discuss potential paths can lead an model consistent data,...
Abstract The Juno spacecraft measured Jupiter’s gravity field and determined the even odd zonal harmonics, J n , with unprecedented precision. However, interpreting these observations has been a challenge because it is difficult to reconcile unexpectedly small magnitudes of moments 4 6 conventional interior models that assume large, distinct core rock ice. Here we show entire set harmonics can be matched an ab initio equation state, wind profiles, dilute heavy elements are distributed as far...
The Juno mission has provided measurements of Jupiter s gravity field with an outstanding level accuracy, leading to better constraints on the interior planet. Improving our knowledge internal structure is key understanding its formation and evolution but also important in framework exoplanet exploration. In this study, we investigated differences between state-of-the-art equations state their impact properties models. Accounting for uncertainty hydrogen helium equation state, assessed span...