October 21, 2009
American Center for Physics
College Park, MD
Speaker: Steve Obenschain
Abstract: Over the past 20 years the NRL program has concentrated on developing and utilizing the electron-beam-pumped krypton-fluoride (KrF) laser for inertial fusion. KrF has the deepest UV light of all high energy ICF lasers and can also provide the most uniform target illumination. Simulations indicate that these qualities will substantially help towards obtaining the high target gains that would be needed for laser fusion power plants. NRL has the world's largest KrF laser (Nike) that is used for target experiments, and has developed the most capable high-energy high-repetition-rate (5 Hz) KrF laser technology (Electra facility). This presentation will provide a overview of progress in the high gain pellet designs, the supporting Nike target experiments, and the KrF laser development. The program has identified a potential "Fast Track" to fusion energy centered about use of a KrF laser and recently developed high-performance direct-drive target designs. The proposed development path exploits the modular nature of the laser driver and other subsystems. Recent advances in the critical IFE science and technologies have increased the attractiveness of this approach.
Biography: Dr. Obenschain heads the laser fusion program at the Naval Research Laboratory that includes research efforts in laser-plasma interaction experiments, in large scale simulations of pellet implosions, in development of high-energy krypton-fluoride laser technology, and in other critical science and technologies needed for laser inertial fusion energy. He was project manager for the construction of Nike, the world's largest krypton fluoride laser facility. He was co-inventor along, with Dr. Robert Lehmberg, of the induced spatial incoherence (ISI) technique that allows uniform illumination of targets by high-energy lasers. He led the first experimental efforts that showed such beam-smoothing schemes suppress deleterious laser-plasma instability. For this work he was a recipient of the 1993 APS award for Excellence in Plasma Physics Research. He is a fellow of the American Physical Society, Plasma Physics Division. He received a B.S. in physics from the University of Virginia and a Ph. D. in plasma physics from UCLA.