PRELIMINARY STUDIES OF RADIATION COUPLING BETWEEN REMOTE SOFT-X-RAY LASER-AMPLIFIERS

Coupling of a soft X-ray laser beam with a relaying concave mirror in a sequentially pumped amplifier geometry using the Ne-like Ge system has been studied experimentally. Preliminary observations indicate an increase in the spatial coherence of the amplified relayed beam. In addition, near-field imaging of one of the amplifier plasmas shows a double-lobed intensity pattern of the emergent beam indicating refractive guiding of the amplified beam with components both normal and tangential to the target surface.

Proton radiography as an electromagnetic field and density perturbation diagnostic (invited)

Laser driven proton beams have been used to diagnose transient fields and density perturbations in laser produced plasmas. Grid deflectometry techniques have been applied to proton radiography to obtain precise measurements of proton beam angles caused by electromagnetic fields in laser produced plasmas. Application of proton radiography to laser driven implosions has demonstrated that density conditions in compressed media can be diagnosed with million electron volt protons. This data has shown that proton radiography can provide unique insight into transient electromagnetic fields in super critical density plasmas and provide a density perturbation diagnostics in compressed matter.

Electronic Circuit Packages

This invention relates to electronic circuit packages designed to hold high frequency circuits operating particularly, but not exclusively, in the microwave, millimeter wave, and sub-millimeter wave bands. The invention provides a package incorporating a cavity in a material for containment of the circuits, wherein the package further incorporates at least one conductive surface mounted on an inner surface extending into the cavity, the conductivity thereof being adapted to be at least partially absorbent to electromagnetic radiation. The conductive surface according to the present invention will tend to attenuate electromagnetic radiation present within the cavity, and so help to prevent undesired coupling from one point to another within the cavity. The conductivity of the conductive material is preferably arranged to match the impedance of the radiation mode estimated or computed to be present within the cavity.

Scattering theory of cooling and heating in optomechanical systems

We present a one-dimensional scattering theory which enables us to describe a wealth of effects arising from the coupling of the motional degree of freedom of scatterers to the electromagnetic field. Multiple scattering to all orders is taken into account. The theory is applied to describe the scheme of a Fabry-Perot resonator with one of its mirrors moving. The friction force, as well as the diffusion, acting on the moving mirror is derived. In the limit of a small reflection coefficient, the same model provides for the description of the mechanical effect of light on an atom moving in front of a mirror.

Poincare Analysis of Non-linear Electromagnetic Modes in Electron-Positron Plasmas

We present an investigation of coupled nonlinear electromagnetic modes in an electron-positron plasma by using the well established technique of Poincaré surface of section plots. A variety of nonlinear solutions corresponding to interesting coupled electrostatic-electromagnetic modes sustainable in electron-positron plasmas is shown on the Poincaré section. A special class of localized solitary wave solution is identified along a separatrix curve and its importance in the context of electromagnetic wave propagation in an electron-positron plasma is discussed.

New generalized dispersion relation for low-frequency electromagnetic waves in Hall-magnetohydrodynamic dusty plasma

A generalized linear theory for electromagnetic waves in a homogeneous dusty magnetoplasma is presented. The waves described are characterized by a frequency which is much smaller (larger) than the electron gyrofrequency (dust plasma and dust gyrofrequencies), and a long wavelength (in comparison with the ion gyroradius and the electron skin depth). The generalized Hall- magnetohydrodynamic (GH-MHD) equations are derived by assuming massive charged dust macroparticles to be immobile, and Fourier transformed to obtain a general dispersion relation. The latter is analyzed to understand the influence of immobile charged dust grains on various electromagnetic wave modes in a magnetized dusty plasma.