LLE Annual Report
The fiscal year ending September 2013 (FY13) included the first six months of the fourth five year renewal of Cooperative Agreement DE-NA0001944 with the U.S. Department of Energy (DOE). A portion of the year was funded as an extension of the prior Cooperative Agreement DE-FC52-08NA2832 with DOE. This annual report summarizes work carried out under the Cooperative Agreement at the Laboratory for Laser Energetics (LLE) during the past fiscal year including work on the inertial confinement fusion (ICF) campaign; laser, optical materials, and advanced technology development; operation of the Omega Facility for the ICF and high-energy-density (HED) campaigns, the National Laser Users' Facility (NLUF), the Laboratory Basic Science (LBS) Program, and other external users; and programs focusing on the education of high school, undergraduate, and graduate students during the year.
Progress in Inertial Confinement Fusion Research
One of LLE's principal missions is to conduct research in ICF with particular emphasis on supporting the goal of achieving ignition on the National Ignition Facility (NIF). This program uses the Omega Laser Facility and the full experimental, theoretical, and engineering resources of the laboratory. During FY13, a total of 1984 target shots were taken at the Omega Laser Facility (comprised of the 60-beam OMEGA UV laser and the four-beam, high-energy petawatt OMEGA EP laser). More than 40% of the facility's target shots in FY13 were designated as ICF experiments or experiments in support of ICF. During the last five years, 8204 target shots were taken on the Omega Laser Facility in support of the National Nuclear Security Administration (NNSA) missions. The OMEGA and OMEGA EP lasers attained average experimental effectiveness of 96.6% and 93.7%, respectively, in FY13.
LLE plays a lead role in the validation of the performance of cryogenic target implosions, essential to all forms of ICF ignition. LLE is responsible for a number of critical elements within the Integrated Experimental Teams supporting the demonstration of indirect-drive ignition on the NIF and is the lead laboratory for the validation of the polar-drive (PD) approach to ignition on the NIF. LLE has also developed, tested, and constructed a number of diagnostics that are being used at both the Omega Facility and the NIF. During this past year, progress in the inertial fusion research program continued in three principal areas: ICF experiments and experiments in support of ICF; theoretical analysis and design efforts aimed at improving direct-drive–ignition capsule designs (including polar-drive–ignition designs) and advanced ignition concepts such as shock ignition and fast ignition; and development of diagnostics for experiments on the NIF, OMEGA, and OMEGA EP. In this volume, we report in detail on these efforts.
Lasers, Optical Materials, and Advanced Technology
The Laboratory's efforts in the development of advanced high-power lasers and optical materials in support of its inertial fusion and high-energy-density research programs is also covered in this volume, including: the design of a new solid-state, high-voltage pulse generator for driving large-aperture Pockels cells; the performance of OMEGA EP seeded by optical pulses with high-frequency phase modulation is demonstrated; modeling and simulation results describing the propagation of spatially dispersed frequency-modulated optical pulses are presented; research on the fracture mechanics of delamination defects in multilayer dielectric coatings is reported; and a process is demonstrated for producing ultra-broadband coatings (for femtosecond pulse applications) with high reflectivity, high-laser-damage thresholds, and controlled dispersion.
FY13 Omega Facility Report
During FY13, the Omega Facility conducted 1408 target shots on OMEGA and 576 target shots on OMEGA EP for a record total of 1984 target shots for the ICF, HED, NLUF, and LBS program. The facility also provided several shot days for CEA and the University of Michigan's Center for Radiative Shock Hydrodynamics (CRASH) program. OMEGA averaged 11.5 target shots per operating day with availability and experimental effectiveness averages for FY13 of 93.9% and 96.6%, respectively. OMEGA EP averaged 6.7 target shots per operating day with availability and experimental effectiveness averages for FY13 of 93.8% and 93.7%, respectively.
National Laser Users' Facility and External Users' Programs
Under the facility governance plan that was implemented in FY08 to formalize the scheduling of the Omega Laser Facility, Omega Facility shots are allocated by campaign. Nearly 70% of the FY13 target shots were conducted for the ICF and HED campaigns.
The fundamental science campaigns accounted for ~27% of the target shots taken by the facility in FY13. Half of these were taken for the National Laser Users' Facility (NLUF) program and the remainder for the Laboratory Basic Science (LBS) program.
The Omega Facility is also being used for several campaigns by teams from the Commissariat á l'Énergie Atomique (CEA) of France and th'e Atomic Weapons Establishment (AWE) of the United Kingdom. These programs are conducted at the facility on the basis of special agreements put in place by DOE/NNSA and the participating institutions.
The facility users during FY13 included 11 collaborative teams participating in the NLUF program; 16 teams led by Lawrence Livermore National Laboratory (LLNL) and LLE scientists participating in the LBS program; many collaborative teams from LLE and the national laboratories conducting ICF experiments; investigators from LLNL and Los Alamos National Laboratory (LANL) carrying out HED experiments; and scientists and engineers from CEA, AWE, and the University of Michigan's CRASH program. In total, ~62% of the Omega facility target shots were conducted by teams led by external users. The work of these external users is summarized in this report.
OMEGA Laser Facility Users Group (OLUG)
The fifth Omega Users Group (OLUG) Workshop was conducted at LLE in April 2013. More than 100 researchers from 25 universities met at the 2.5-day workshop to facilitate communications and exchanges among individual Omega users and between users and the LLE management; to present ongoing and proposed research; to encourage research opportunities and collaborations that could be undertaken at the Omega facility and other high-energy-density-physics facilities; to provide an opportunity for students, postdoctoral fellows, and young researchers to present their research in an informal setting; and to provide feedback to the LLE management from the users about ways to improve the facility and future experimental campaigns. A summary report on this workshop is contained in this report.
As the only major university participant in the National ICF Program, education continues as an important mission for LLE. The Laboratory's education programs are covered in this report including: the high school summer research program that involved 15 students chosen from Rochester-area high schools; the undergraduate program which involved 40 students who participated in work or research projects at LLE this past year; and the graduate education and training program that included 60 graduate students who worked on graduate thesis research programs at LLE during the year, including 37 students pursuing a Ph.D. through the NNSA-sponsored Horton Graduate Fellowship program at LLE; in addition, more than 60 graduate and undergraduate students from other academic institutions were involved in Omega Facility research as members of participating NLUF teams in FY13.
Table of Contents
- A Polar-Drive Shock-Ignition Design for the National Ignition Facility
- Polar-Drive Implosions on OMEGA and the National Ignition Facility
- Cross-Beam Energy Transfer in Polar-Drive Implosions on OMEGA
- Measured Hot-Electron Intensity Thresholds Quantified by a Two-Plasmon–Decay Resonant Common-Wave Gain in Various Experimental Configurations
- Mitigation of Cross-Beam Energy Transfer: Implications of Two-State Optical Zooming on OMEGA
- Measuring 8- to 250-ps Short Pulses Using a High-Speed Streak Camera on Kilojoule, Petawatt-Class Laser Systems
- A Solid-State, Inductive-Adder, 10-kV Pulse Generator for Driving Large-Aperture Pockels Cells
- Commissioning of a Multiple-Frequency–Modulation Smoothing by Spectral Dispersion Demonstration System on OMEGA EP
- Simulations of the Propagation of Multiple-FM Smoothing by Spectral Dispersion on OMEGA EP
- Fiber Front End with Multiple Phase Modulations and High-Bandwidth Pulse Shaping
- Mitigation of Two-Plasmon Decay in Direct-Drive Inertial Confinement Fusion Through the Manipulation of Ion-Acoustic- and Langmuir-Wave Damping
- Hot-Electron Generation from Laser/Pre-Plasma Interactions in Cone-Guided Fast Ignition
- Pulsed Laser Ablation of Dental Calculus in the Near-Ultraviolet
- Improving Cryogenic DT Implosion Performance on OMEGA
- Polar-Drive Experiments with Shimmed Targets on OMEGA
- Localized Time-Resolved Electron-Temperature Measurements Indicate Nonuniformly Driven Two-Plasmon–Decay Instability in Direct-Drive Implosions
- Measurements of the Divergence of Fast Electrons in Laser-Irradiated Spherical Targets
- Copper K-Shell Emission Cross Sections for Laser–Solid Experiments
- Fracture Mechanics of Delamination Defects in Multilayer Dielectric Coatings
- Demonstration of the Improved Rocket Efficiency in Direct-Drive Implosions by Using Different Ablator Materials
- Characterization of a High-Photon-Energy X-Ray Imager
- Plasma-Ion–Assisted Coatings for 15-fs Laser Systems
- Spectral and Temporal Properties of Optical Signals with Multiple Sinusoidal Phase Modulations
- The Fifth Omega Laser Facility Users Group Workshop
- LLE's Summer High School Research Program
- FY13 Laser Facility Report
- National Laser Users' Facility and External Users' Programs
- Publications and Conference Presentations