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Speculative models of the interiors of the terrestrial planets. All are rocky, divided into a crust (not shown here), mantle, and metallic core. (After R. T. Merrill and M. W. McElhinny, The Earth's Magnetic Field, Academic Press, 1983)

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from article Earth's interior

Preliminary Reference Earth Model (PREM) for P- and S-wave velocities, vp and vs, and density ρ. In the part of the upper mantle where the model is anisotropic, velocities are given in both the vertical and horizontal direction. The broken lines…

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from article Earth's interior

Variations of gravity and pressure inside the Earth. 1 m = 3.3 ft. 1 megabar = 100 GPa. (After P. Melchior, The Physics of the Earth's Core, Pergamon Press, 1986)

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from article Earth's interior

Density versus depth for several mantle constituents along the 1400°C (2552°F) adiabat. Data points show the density variation of PREM. All three constituents shown here contain magnesium-rich silicates. (After D. L. Anderson, Where on Earth is the…

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from article Earth's interior

P-wave velocity anomalies above the core–mantle boundary in terms of spherical harmonics up to degree and order 6, obtained by inverting P-wave travel time data. Positive perturbations indicate faster-than-average material. Contour interval = 25…

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from article Earth's interior

Speculative, schematic model of the core–mantle boundary layer. A heterogeneous chemical boundary layer is embedded in a thermal boundary layer. Large-scale mantle circulation transports chemical heterogeneity to the base of the mantle as well as…

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from article Earth's interior

Schematic temperature profile of the mantle. Subsequent estimates of core temperature are higher than suggested in the figure; the temperature jump across the thermal boundary layer at the base of the mantle will then be correspondingly higher. °F =…

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from article Earth's interior

Schematic temperature profile of the core. The melting-point curve for the core is substantially below the melting point of pure iron. All temperatures may have to be raised to correspond with further estimates of the melting point of iron. °F = (K…

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from article Earth's interior

Contour plots of the radial component of the magnetic field at the core–mantle boundary (a) for the year 1715 and (b) for 1980. The contour interval is 100 microteslas; solid-line contours represent flux into the core, and broken-line contours…

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from article Triple point

Phase diagram for water, showing gas, liquid, and several solid (ice) phases; triple points at A, B, and C. The pressure scale changes at 101 kilopascals from logarithmic scale at low pressure to linear at high pressure.

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from article Inertial confinement fusion

Ablative indirect drive and ablative direct drive. (a) In laser-illuminated, ablative indirect drive, the ICF target consists of a cylindrical hohlraum (hollow room) in which laser light is injected through the two holes in the end caps and heats…

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from article Inertial confinement fusion

X-ray images with a framing camera (developed at Lawrence Livermore National Laboratory) from a directly driven inertial confinement fusion capsule at the University of Rochester's Omega Facility. The camera has 80-ps exposure time and 55-ps time…

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from article Inertial confinement fusion

Deuterium–tritium fuel ion temperature and density at ignition, plotted against normalized radius, for a typical high-gain capsule.

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from article Inertial confinement fusion

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). Its driver is the world's largest laser. The 1.8 MJ of ultraviolet light (351-nm wavelength from frequency-tripled neodymium:glass laser light) is generated with…

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from article Inertial confinement fusion

Progress toward ignition on NIF is illustrated by the plot of no-burn D–T equivalent yield in number of neutrons versus the value of ρr inferred from the energy lost by fusion neutrons during passage out of the compressed fuel. These experiments…

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from article Inertial confinement fusion

View of the combined Z Machine and Z-Beamlet laser facility (lower left) with exploded view of the cross section of the Z Machine (upper left). Both will be used to drive the MagLIF capsule (right) at Sandia National Laboratories. The 10-kJ…

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from article Inertial confinement fusion

Computed capsule gains (energy yield divided by absorbed energy) from 1D simulations of the principal (radial) dynamics for ablative direct drive of a perfect capsule, which is irradiated by either 248-nm laser light or 351-nm laser light with…

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from article Inertial confinement fusion

Electra, an ∼500 J/pulse, electron-beam pumped KrF laser at the Naval Research Laboratory. It has achieved 90,000 shots in a continuous run and 330,000 shots in 8 days at 2.5–5 Hz.

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from article Inertial confinement fusion

Conceptual design of the X-target. (Credit: Heavy Ion Fusion Science Virtual National Laboratory)

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from article Renner-Teller effect

Bending potential function V for a degenerate electronic state of a linear molecule as a function of displacement r, and for three values (0, 0.5, 1.0) of the Renner parameter ε. In the absence of Renner-Teller splitting (ε = 0) there is a single…

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from article Capacitance

Parallel-plate capacitor P1, P2 with guard ring GG. Spacing between guard ring and plate is exaggerated. (a) Cross section with all parts of capacitor at ground potential. (b) Top view showing plate P1 surrounded by guard ring. (c) Cross section of…

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from article Capacitance