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The effect of relaxing the local-spatial-periodicity assumption on the space-charge field in parametric codes is examined. Corrections to the original model are important when the space-charge reduction factor depends strongly on the wave length.

Research describing the complex dielectric permittivity of lossy ceramic composites is presented. In particular an AlN composite is investigated with regard to the phasing out of BeO composites on environmental and safety grounds.

Researchers observed nonuniform heating of zinc oxide powder undergoing microwave heating in an oxygen-deficient atmosphere. Real-time surface and core temperature measurements demonstrated that a zone of localized heating propagated from the core outwards. This phenomenon does not occur during heating in air. The researchers suggest that adsorption oxygen from the atmosphere counterbalances the effect of water desorption on the complex permittivity. This implies that changes to surface chemistries could, in some circumstances, permit self-limiting heating using microwaves.

The local elimination of halocarbons from air by high-power microwave sources is studied. The destruction of halocarbons can be due to free electrons produced in a freely localized discharge started in the air by a focused microwave beam. After rapid cooling, the electrons can link with halocarbon molecules and destroy them. Operating regimes and their efficiencies are examined and the corresponding parameters of microwave sources are specified.

The influence of porosity on the complex dielectric permittivity of microwave sintered zinc oxide at room temperature and 2.45 GHz was investigated. Calculations using conventional Maxwell-Garnet theory and the effect medium approximation were not in agreement with empirical results. A model that assumes the presence of dielectrically inactive, fractal-geometry boundaries between ceramic grains offers an excellent description of the results with no free parameters.

Detailed experimental studies on sheet relativistic electron beam propagation through a long planar wiggler are reported and compared with numerical simulations. The planar wiggler has 56 periods with a period of 9.6 mm. Typically, the wiggler field peak amplitude is 5 kG. The experimental efforts have been focused on control of the deviation of the beam toward the side edge of the planar wiggler along the wide transverse direction. It is found that a suitably tapered magnetic field configuration at the wiggler entrance can considerably reduce the rate of the deviation. The effects of the following techniques on beam transport efficiency are also discussed: side focusing, beam transverse velocity tuning at the wiggler entrance, and beam spread limiting. High beam transport efficiency (almost 100%) of a 15 A beam has been obtained in some cases. The results are relevant to development of a free electron laser amplifier for application to stabilizing and heating of plasma in magnetic fusion research.

Presents an analysis of the radiation from betatron oscillations for the stellatron, a strong-focused betatron, to diagnose the energy of an electron beam propagating in a focusing channel. Particle orbits in the stellatron; Standard expression for radiated intensity for prescribed particle motion; Effect of geometric line broadening, an inhomogeneous broadening mechanism due to orbit curvature.

Details a calculation on spontaneous radiation emitted by an electron beam passing through a continuously rotating quadrupole magnetic undulator. Information on the use of free-electron laser; Equations of motion; Characteristics of the radiation spectrum.

Provides information on the components of simple-particle trajectories of relativistic electrons in a magnetic field configuration. Analysis of gain mechanism in free-electron laser devices; Particle orbit equations; Stability analyses.

Presents a study which reduced the free-electron-laser (FEL) equations to a set of one-dimensional, normalized equations that allow a universal dimensional analysis. Performance characteristics of specific high-gain FEL; Estimates for the efficiency enhancement achieved with a tapered section; Design of high-gain millimeter-wave FEL amplifier using a superconducting short-period wiggler and sheet electron beam.

Presents procedures and quantitative analyses for obtaining and evaluating experimental short-period-wiggler free-electron lasers (FEL) oscillators that have been optimized with respect to efficiency. Applications for candidate sources of high-power, tunable, coherent radiation; Equilibrium operating point for the FEL oscillator; Effects of beam axial energy spread on the FEL interaction efficiency.