LLE 1997. Annual report, October 1996--September 1997

The fiscal year ending September 1997 (FY97) concluded the fifth year of the cooperative agreement (DE-FC03-92SF19460) with the U.S. Department of Energy (DOE). This report summarizes research at the Laboratory for Laser Energetics (LLE) and is the final report for the first five years of the cooperative agreement. In September 1997, the cooperative agreement was renewed for an additional five years. We summarize our research during FY97, the operation of the National Laser Users` Facility (NLUF), and the education of high school, undergraduate, and graduate students in LLE programs. A general introduction to LLE`s experimental physics program and a report on recent results are found on pp. 161-167. This article includes a useful summary of the system`s operational capabilities and system parameters after three years of operation. Direct-drive inertial confinement fusion requires precise drive uniformity, the control of hydrodynamic instabilities during the implosion of the fusion target, and accurate target fabrication and characterization. The article summarizes a wide variety of experiments relating to direct-drive laser fusion, from high-yield implosion experiments to planar and spherical Rayleigh-Taylor experiments, laser-imprinting experiments, and laser-plasma interaction experiments. A detailed analysis of the equation of motion for an electron in a plane wave is presented beginning on p. 24. A guiding center model is postulated and compared to numerical simulation of the actual particle motion. The formula is also verified analytically using the method of multiple scales. Work continues on this formalism to study the effects of the pondermotive force on laser-plasma interactions. A theoretical calculation of the dephasing time of an electron accelerated by a laser pulse is found on pp. 92-100. The trajectory of a charged particle, determined analytically for various pulse shapes, is then used to determine the dephasing time of an accelerated particle