August 21, 2013
Naval Research Laboratory Laser Plasma Branch
Twenty-five years ago the NRL laser fusion program and other labs switched from the ubiquitous flash-lamp pumped Nd-glass laser to developing and utilizing the krypton-fluoride excimer laser for Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP) research. The KrF laser has distinct advantages for ICF experiments including deeper UV wavelength (248 nm), which improves the efficiency of the laser target coupling and helps suppress undesired laser-plasma instability, as well as its capability to provide extremely uniform target illumination. In 1995 NRL completed the Nike KrF system. Nike (named for the Greek goddess of victory) demonstrated that multi-kilojoule KrF systems could be operated with sufficient flexibility and reliability to be a research tool for ICF. Nike has the most advanced and flexible scheme for achieving highly uniform target illumination and is the only laser facility with the demonstrated capability to zoom down the focal diameter during a laser pulse. Nike is the world’s largest KrF laser and can provide up to 3 kJ on target.
In addition to Nike, the Branch has developed a high repetition rate (5 Hz) 700 J KrF facility called Electra (mythical princess of Argos, daughter of Agamemnon and Clytemnestra). Such high repetition rates would be needed for power generation by inertial fusion. Other uses of Electra’s pulsed high-power electron beams are being explored, such as surface hardening of materials and using the beams to catalyze chemical reactions.
Description of Current Research by Laser Plasma Branch
The Laser Plasma Branch primary research efforts are in support of the Nation’s Inertial Confinement Fusion (ICF) program. This work includes: conducting laser-plasma interaction experiments with the Nike KrF laser facility; developing advanced radiation hydrocodes and the theory of laser target interactions; conducting simulations of laser target interactions in support of experiments and to design robust high performance targets for inertial fusion; and developing KrF laser technology for inertial fusion. Experiments include basic studies of hydrodynamic instabilities of laser accelerated planar targets, high pressure shocks, radiation from laser irradiated targets and laser plasma instabilities. FASTRAD3D, a 3D massively parallel Eulerian based radiation hydrodynamics code, supports the experiments and also is the primary tool for designing ICF targets. Our group will visit the Nike and Electra laboratories and will hear a talk describing the current research of the Laser Plasma Branch. The visit will take about two hours. The Naval Research Laboratory (NRL) is located in the Southwest quadrant of Washington,4555 Overlook Ave. SW., Washington, DC 20375, convenient to downtown, the Pentagon, just 15 minutes from ACP, and sits just across the Potomac River from Old Town Alexandria, Virginia at Exit 1 from I-295 S. Parking instructions will be sent to attendees by e-mail when available.
NRL is a controlled-access facility. Those who wish to join us must register with the MASPG coordinator for this tour, Dave Ross (firstname.lastname@example.org), prior to August 1, 2013, providing your name, birth date, citizenship, phone number and email address (for communication of tour details and instructions for entering NRL).