Recently, artificially constructed metamaterials have become of considerable interest, because these materials can exhibit electromagnetic characteristics unlike those of any conventional materials. Artificial magnetism and negative refractive index are two specific types of behavior that have been demonstrated over the past few years, illustrating the new physics and new applications possible when we expand our view as to what constitutes a material. In this review, we describe recent advances in metamaterials research and discuss the potential that these materials may hold for realizing new and seemingly exotic electromagnetic phenomena.

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Metamaterials and negative refractive index.

Recent theory has predicted a superlens that is capable of producing sub–diffraction-limited images. This superlens would allow the recovery of evanescent waves in an image via the excitation of surface plasmons. Using silver as a natural optical superlens, we demonstrated sub–diffraction-limited imaging with 60-nanometer half-pitch resolution, or one-sixth of the illumination wavelength. By proper design of the working wavelength and the thickness of silver that allows access to a broad spectrum of subwavelength features, we also showed that arbitrary nanostructures can be imaged with good fidelity. The optical superlens promises exciting avenues to nanoscale optical imaging and ultrasmall optoelectronic devices.

http://science.sciencemag.org/content/sci/308/5721/534.full.pdf

Sub-Diffraction-Limited Optical Imaging with a Silver Superlens

A universal instability of many-dimensional oscillator systems

Artificially engineered metamaterials are now demonstrating unprecedented electromagnetic properties that cannot be obtained with naturally occurring materials. In particular, they provide a route to creating materials that possess a negative refractive index and offer exciting new prospects for manipulating light. This review describes the recent progress made in creating nanostructured metamaterials with a negative index at optical wavelengths, and discusses some of the devices that could result from these new materials.

/pdf/optical-negative-index-metamaterials-2q5qafgl3m.pdf

Optical negative-index metamaterials

Inertial confinement fusion (ICF) is an approach to fusion that relies on the inertia of the fuel mass to provide confinement. To achieve conditions under which inertial confinement is sufficient for efficient thermonuclear burn, a capsule (generally a spherical shell) containing thermonuclear fuel is compressed in an implosion process to conditions of high density and temperature. ICF capsules rely on either electron conduction (direct drive) or x rays (indirect drive) for energy transport to drive an implosion. In direct drive, the laser beams (or charged particle beams) are aimed directly at a target. The laser energy is transferred to electrons by means of inverse bremsstrahlung or a variety of plasma collective processes. In indirect drive, the driver energy (from laser beams or ion beams) is first absorbed in a high‐Z enclosure (a hohlraum), which surrounds the capsule. The material heated by the driver emits x rays, which drive the capsule implosion. For optimally designed targets, 70%–80% of the d...

/pdf/development-of-the-indirect-drive-approach-to-inertial-314a4yq250.pdf

Development of the indirect‐drive approach to inertial confinement fusion and the target physics basis for ignition and gain

Statistical description of stochastic orbits in a Tokamak

Advances in the theory of ion-temperature-gradient-driven turbulence

In the IGNITEX (Fusion Ignition Experiment) device, the plasma is surrounded by massive conducting material composed of several layers. From inside to outside, the layers may be categorized as: first wall-vacuum vessel, poloidal-field magnet system, inner toroidal-field magnet region with slits, and an outer homogeneous toroidal-field magnet region divided into twelve sectors. The 2-D finite-element program PROTEUS is used to study current induction and plasma equilibrium throughout the ignition discharge. Some modifications of the original code PROTEUS which permit the study of compact plasmas with strong wall coupling are described. The structure layers are simulated either as diffusive or as a set of electric circuits properly connected. Different resistivity models are considered. The calculations presented show that the flux swing produced by the poloidal-field (PF) coil system is enough to induce over 12 MA of plasma current and that a sequence of equilibrium configurations with elliptical cross sections can be obtained by properly choosing the waveforms of the PF system currents throughout the discharge of 10 s. >

Structural eddy current effects on plasma equilibrium and current induction in the IGNTEX experiment

Small and large versions of the Fusion Ignition Experiment (IGNITEX) are defined with emphasis on their physics basis. The models used for their definition are given. Results of volume-averaged calculations and a probabilistic analysis are included. The small and large versions of the experiment are being considered in an effort to define both the smallest experiment that can produce fusion ignition under physics scaling pertinent to ohmically-heated, high-field tokamaks, and the smallest experiment that can produce fusion ignition using the most pessimistic extrapolation of the scaling laws based on the auxiliary heating L-mode database. >

Marshall N. Rosenbluth

Papers

Statistical description of stochastic orbits in a Tokamak

Advances in the theory of ion-temperature-gradient-driven turbulence

Structural eddy current effects on plasma equilibrium and current induction in the IGNTEX experiment

Analysis of the small and large versions of the IGNITEX experiment

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