Feasibility of an electromagnetic railgun as a high-velocity (;sl 10 km/s) hydrogen pellet injector for refueling magnetic fusion reactors is investigated both experimentally and theoretically. A variety of advanced railgun configurations are considered, especially those which rely on magnetic propulsion of the pellet by a plasma-arc armature and which do not require a fuse to effect the system operation. The principal diagnostics used are laser interferometry, optical spectroscopy, streak camera, and magnetic probes. A CAMAC system is employed for data acquisition and processing. Using the present acceleration scheme a solid hydrogen pellet velocity in the range of 3.3 km/s has been demonstrated.

A novel scheme using field-injection electrohydrody namic spraying of liquid-mix precursors is investigated for development of a method for fabricating thin films of metals, semiconductors, superconductors, and insulators. The same technique is also suitable for fabricating nanoparticles from a variety of liquid precursors. Unique aspects of this new technique are that it is inherently capable of producing a uniform, charged fine spray of liquid precursors of controlled size, chemical composition, and stoichiometry, and that the energy of the spray can be controlled, allowing for fabrication of high-quality films and uniform nanoparticles.

This work is intended to develop techniques that are most suitable for noncontact coating of spherical ICF targets. The work involves developing two different techniques: one that can stably levitate a microsphere a few hundred microns to a few milimeters in diameter and the other that can produce uniform coating on a levitated small object. The levitation schemes include acoustic and gas dynamic methods. The coating technique being investigated is known as the charged liquid-cluster beam technique in which a liquid precursor is sprayed into charged nanodrops which in turn are directed toward the levitated object.

The objective of this work is to grow device-quality GaN-based films for fabrication of short-wavelength optical devices and high-speed, high-power electronic devices. The growth technique used is the plasma-assisted ionized source beam epitaxy that employs an atomic nitrogen beam from an rf-discharge nitrogen plasma and a partially ionized Ga source beam. The growth system is one designed and fabricated at the University of Illinois, and the nitrogen plasma source is uniquely capable of producing contamination-free plasmas. The films are characterized using a variety of microanalysis techniques including RHEED, XRD, SEM, and TEM.