2016 Annual Report
The fiscal year ending September 2016 (FY16) concluded the first 42 months of the fourth five year renewal of Cooperative Agreement DE-NA0001944 with the U.S. Department of Energy (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 Laser 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.
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 at the National Ignition Facility (NIF). This program uses the Omega Laser Facility and the full experimental, theoretical, and engineering resources of the laboratory. During FY16, a record 2193 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). In FY16, 72% of the facility’s target shots were carried out for ICF and HED Campaigns.
LLE plays a lead role in validating the performance of cryogenic target implosions, essential to all forms of ICF ignition. LLE is responsible for a number of critical elements within theIntegrated Experimental Teams that support the demonstration of indirect-drive ignition on the NIF and is the lead laboratory for the validation of the direct-drive–ignition approach on the NIF. LLE has also developed, tested, and constructed a number of diagnostics that are being used at both the Omega Laser 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 direct-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.
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 HED research programs is also covered in this volume, including work on: the contribution of thin-film interfaces to the near-ultraviolet absorption and pulsed-laser–induced damage for ion-beam–sputtered and electron-beam–evaporated coatings; development of a simple diagnostic to characterize 1-D chromatic aberrations in a broadband beam; work on the development of an eight-channel, time-multiplexed pulse-shaping system that generates, demultiplexes, and retimes optical waveforms from a single pulse-shaping unit; a design approach to continuous distributed phase plates (DPP’s) using the code Zhizhoo’ (p. 74); research on experimental efforts to correlate the mechanical properties of multilayer diffraction gratings to laser-induced–damage thresholds (LIDT’s); and the first complete set of measurements of a laser-plasma optical system’s refractive index, as seen by an independent probe laser beam, as a function of the relative wavelength shift between the two laser beams.
FY16 Omega Facility Operations
During FY16, the Omega Laser Facility conducted 1414 target shots on OMEGA and 779 target shots on OMEGA EP for a total of 2193 target shots [see Tables 148.IX and 148.X (p. 202)]. OMEGA averaged 11.7 target shots per operating day with Availability and Experimental Effectiveness averages of 95.6% and 96.6%, respectively.
OMEGA EP was operated extensively for a variety of internal and external users. A total of 718 target shots were taken into the OMEGA EP target chamber and 61 joint target shots were taken into the OMEGA target chamber. OMEGA EP averaged 7.9 target shots per operating day with Availability and Experimental Effectiveness averages of 96.9% and 95.8% respectively. Per the guidance provided by DOE/NNSA (National Nuclear Security Administration), the facility provided target shots for the ICF, HED, NLUF, and LBS programs. The facility also provided a small number of shots for Commissariat á l’énergie atomique et aux energies alternatives (CEA) (see Fig. 1). In FY16, 72% of the target shots were taken for the ICF and HED Campaigns.
National Laser Users’ Facility and External Users Programs
The Omega Laser Facility was also used for several campaigns by teams from CEA of France. The facility users during this year included 13 collaborative teams participating in the NLUF Program; 14 teams led by Lawrence Livermore National Laboratory (LLNL) and LLE scientists participating in the LBS Program; many collaborative teams from the national laboratories conducting ICF experiments; investigators from LLNL, Los Alamos National Laboratory (LANL), and Sandia National Laboratories (SNL) conducting experiments for high-energydensity–physics programs; and scientists and engineers from CEA.
Omega Laser Facility Users Group
A capacity gathering of 110 researchers from around the world met at LLE for the Eighth Omega Laser Facility Users Group (OLUG) 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 Laser Facility and in a complementary fashion at other facilities [such as the NIF or the Laboratoire pour l’Utilisation des Lasers Intenses (LULI)]; to provide an opportunity for students, postdoctoral fellows, and young researchers to present their research in an informal setting; and to provide feedback from the users to LLE management about ways to improve and keep the facility and future experimental campaigns at the cutting edge.
The high school program involved 13 students chosen from Rochester-area high schools. The projects were related to current research activities at LLE and covered a broad range of areas of interest including laser physics, computational modeling of implosion physics, experimental diagnostics development, pulsed-power development, ultra-intense laser–matter interactions, simulation of magnetized-liner inertial fusion, cryogenic target characterization, and interactive data analysis.
Thirty-nine undergraduate students participated in work or research projects at LLE this past year. Student projects include operational maintenance of the Omega Laser Facility; work in laser development, materials, and optical thin-film coating laboratories; computer programming; image processing; and diagnostics development. This is a unique opportunity for students, many of whom will go on to pursue a higher degree in the area in which they gained experience at LLE. In FY16, 62 graduate students were involved in research projects at LLE, and LLE directly sponsored 36 students pursuing Ph.D. degrees via the NNSA-supported Frank Horton Fellowship Program in Laser Energetics. Their research includes theoretical and experimental plasma physics, HED physics, x-ray and atomic physics, nuclear fusion, ultrafast optoelectronics, high-power laser-development and applications, nonlinear optics, optical materials and optical fabrication technology, and target fabrication. In addition, LLE directly funded research programs within the MIT Plasma Science and Fusion Center, the State University of New York (SUNY) at Geneseo, and the University of Wisconsin.