Fluid dynamics of planetary ices
نویسنده
چکیده
The role of water ice in the solar system is reviewed from a fluid-dynamical point of view. On Earth and Mars, water ice forms ice sheets, ice caps and glaciers at the surface, which show glacial flow under their own weight. By contrast, water ice is a major constituent of the bulk volume of the icy satellites in the outer solar system, and ice flow can occur as thermal convection. The rheology of polycrystalline aggregates of ordinary, hexagonal ice Ih is described by a power law, different forms of which are discussed. The temperature dependence of the ice viscosity follows an Arrhenius law. Therefore, the flow of ice in a planetary environment constitutes a thermo-mechanically coupled problem; its model equations are obtained by inserting the flow law and the thermodynamic material equations in the balance laws of mass, momentum and energy. As an example of gravity-driven flow, the polar caps of Mars are discussed. For the north-polar cap, large-scale flow velocities of the order of 0.1 . . . 1 mm a−1 are likely, locally enhanced by a factor ten or more in the vicinity of surface scarps/troughs. By contrast, the colder south-polar cap is expected to be almost stagnant. Tidally heated convection is discussed for the example of the icy crust of Europa, where a two-dimensional model predicts the formation of an upper, conductive lid and a lower, convective layer with flow velocities of the order of 100 mm a−1. Very little is known about the fluid-dynamical relevance of highpressure phases of water ice as well as ices made up of other materials. GAMM-Mitteilungen 29(1), 29–51 (2006) http://www.interscience.wiley.com/ — Author’s version —
منابع مشابه
Rheological and Thermal Properties of Icy Materials
Laboratory measurements of physical properties of planetary ices generate information for dynamical models of tectonically active icy bodies in the outer solar system. We review the methods for measuring both flow properties and thermal properties of icy planetary materials in the laboratory, and describe physical theories that are essential for intelligent extrapolation of data from laboratory...
متن کاملCarbon precipitation from heavy hydrocarbon fluid in deep planetary interiors.
The phase diagram of the carbon-hydrogen system is of great importance to planetary sciences, as hydrocarbons comprise a significant part of icy giant planets and are involved in reduced carbon-oxygen-hydrogen fluid in the deep Earth. Here we use resistively- and laser-heated diamond anvil cells to measure methane melting and chemical reactivity up to 80 GPa and 2,000 K. We show that methane me...
متن کاملA Massive Core in Jupiter Predicted From First-Principles Simulations
Hydrogen-helium mixtures at conditions of Jupiter’s interior are studied with first-principles computer simulations. The resulting equation of state (EOS) implies that Jupiter possesses a central core of 14 – 18 Earth masses of heavier elements, a result that supports core accretion as standard model for the formation of hydrogen-rich giant planets. Our nominal model has about 2 Earth masses of...
متن کاملUnderstanding the Kinetics and Dynamics of Radiation-induced Reaction Pathways in Carbon Monoxide Ice at 10 K
Carbon monoxide is the second most abundant molecule on icy grains in the interstellar medium. It also exists on Pluto, Triton, comets, and possibly in other icy bodies of the outer solar system like Kuiper Belt objects. With the intense radiation fields that permeate virtually all unprotected regions of space, carbon monoxide ices can be processed through energetic particle bombardment (planet...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2009