Join us for a seminar with Prof. Ivan Oleynik, University of South Florida, titled “Carbon at Extremes: Discovery Science with Exascale Computers and Experiment.”

The seminar will begin at 3:00 PM ET on November 7, 2023.

Please contact Sarah Preis for connection information.

Bio: Ivan Oleynik is a professor at the Department of Physics, University of South Florida. His research focuses on studies of materials at extreme pressures and temperatures by advanced theory, simulations and experiment. He is also best known for design and prediction of properties of novel materials, and development of new methods for materials simulations at atomistic level. He leads several experimental teams to perform experiments at National Ignition Facility at Lawrence Livermore National Laboratory, Sandia’s Z pulsed power facility, Omega laser facility at Laboratory of Laser Energetics to realize groundbreaking predictions from his simulations. He also spearheads several computational campaigns at DOE’s exascale supercomputers, securing the largest computing allocations awarded by DOE’s ASCR Leadership Class Computing Challenge (ALCC) and the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) programs. Ivan also led a team of computational scientists that earned a 2021 Gordon Bell Prize finalist nomination for record-breaking billion-atom simulations of carbon at extreme conditions and experimental time and length scales. He is a Fellow of the American Association for Advancement of Science, the American Physical Society, and the American Vacuum Society.

Optical Physics of Explosive Fireballs

Nick Glumac
Shao Lee Soo Professor of Mechanical Science & Engineering
University of Illinois, Urbana-Champaign

Contact Rachel Wise for connection information.

Fireballs generated by high explosives represent a class of complex thermochemical environments that, despite their utility in engineering and military applications, remain challenging to simulate accurately. Flows are transient and three-dimensional. They involve non-equilibrium effects requiring explicit chemical modeling, and they often consist of multiple phases. Optically, the light emissions from fireballs are similarly complex, temporally and spatially. Early time signatures show extreme, plasma-like conditions, and later-time optical signatures are complicated by spatial property variations, optical depth issues, and limited information on emissivities of explosively generated particulates. This talk discusses the optics of fireballs, covering the evolution of emitted light from an explosive event, with an emphasis on spectroscopic emission measurements. Insight gained in these measurements has led to optical measurements within the fireball itself, primarily in absorption. These measurements are reviewed, and the current state of the art of in-fireball spectroscopy is discussed, with emphasis on the next generation of measurement technologies.

Nick Glumac is the Shao Lee Soo Professor of Mechanical Science & Engineering at the University of Illinois, Urbana-Champaign. He received his Ph.D. from Caltech in 1994. His research focusses on spectroscopy of reacting flows with emphasis on flows involving energetic materials, especially explosives. He is the recipient of a handful of minor awards, most of which were obtained by dubious means. His greatest accomplishments include assisting in research work performed by legendary scientists Tim Weihs, Mike Zachariah, and Ed Dreizin.

Laboratory equation of state measurements of the carbon envelopes of white dwarf stars

Please contact Rachel Wise at [email protected] for connection information.

White dwarfs (WD) represent the final state of evolution for the vast majority of stars 1–3 . Certain classes of white dwarfs pulsate4, 5 , leading to observable brightness variations whose analysis with theoretical stellar models uniquely probes their internal structure. Modeling of these pulsating WD stars provides stringent tests of white dwarf models and a detailed picture of the outcome of the late stages of stellar evolution 6. However, these high energy density states are extremely difficult to access and diagnose in the laboratory and as a result theory is largely untested at these conditions. Here, we present equation of state (EOS) measurements of matter at pressures ranging from 100-450 million atmospheres, where the understanding of WD stars is sensitive to the EOS and where models show significant differences. We measure the pressure-density relationship along the principal shock Hugoniot of hydrocarbon to within five percent. The observed maximum compressibility is consistent with theoretical models that include detailed electronic structure, are used in calculations of WD stars and inertial confinement fusion (ICF) experiments7, 8 , and predict an increase in compressibility due to ionization of the inner core orbitals of car- bon. We also find that detailed treatment of the electronic structure and the electron degeneracy pressure are required to capture the measured shape of the pressure-density evolution for hydrocarbon before peak compression.

Dr. Annie Kritcher is a co-lead within the ICF Integrated Experiments Element and primary designer for campaigns to increase implosion scale on the NIF, and also serves on the ICF leadership team.  Her main responsibilities include setting the strategic direction of the campaign with an experimental co-lead, leading the design effort and post-shot analysis, interpretation of data, collaboration with other campaigns, and interfacing with target fabrication.  Annie currently serves as the chair of the Strategic Initiative and Exploratory Research High Energy Density Science LDRD technical review committee.  She also serves on the Lawrence Fellow selection committee, Dynamic Compression Sector proposal selection committee, and the LCLS MEC peer review panel. 

Annie was first employed at the Lab as a summer intern in 2004, as an LLNL Lawrence Scholar during her time at UC Berkeley, and as a Lawrence postdoctoral fellow in 2009 following completion of her Ph.D.  Annie’s thesis on experimental measurements of X-ray Thomson Scattering to diagnose high energy density matter was conducted at the Jupiter laser facility (LLNL) and Omega laser facility (Rochester).  During her postdoctoral appointment she continued her work on X-ray Thomson Scattering, investigated nuclear plasma interactions, and co-lead a campaign to measure the equation of state of materials to hundreds of Mbars.  She also obtained an LDRD to continue this project after her postdoc.  Following her postdoc she transitioned from experimental physics to design physics within the Design Physics directorate at LLNL where her main focuses included assessing the impact of low mode asymmetries on ICF implosions, ICF ablator material comparison, and increasing ICF implosion scale.

Join us for a seminar with Dr. Rebecca Hersman, director and senior advisor at the Center for Strategic and International Studies (CSIS), titled “Talking Tech: The Importance of Science and Technology Leadership in Policy Decisionmaking.”

The seminar will begin at 3pm ET on April 6, 2021.

Please contact Rachel Wise at [email protected] for connection information.

Abstract: In Countering Weapons of Mass Destruction, a technical solution is only as good as the policy-makers ability to understand, trust and communicate it. Lessons from Fukushima, Libya and Syria show the opportunities and pitfalls of developing technically informed policy options. Lessons that will only become more important in the complex technology driven security environment of the future.

Speaker Bio: Rebecca Hersman is director of the Project on Nuclear Issues (PONI) and senior adviser for the International Security Program at the Center for Strategic and International Studies (CSIS).  A leading expert on nuclear, chemical and biological weapons policy, global health security and crisis management, Ms. Hersman leads the preeminent national program designed to develop next generation nuclear expertise. An author of numerous studies and reports on nuclear and chemical weapons policy, emerging technologies and strategic stability, and crisis management and decision-making, Ms. Hersman also co-chairs the CSIS U.S./U.K./France Trilateral Dialogues on Nuclear Issues and has served as a Commissioner on the CSIS Commission on Strengthening America’s Health Security.

Ms. Hersman joined CSIS in April 2015 from the Department of Defense, where she served as Deputy Assistant Secretary of Defense for Countering Weapons of Mass Destruction since 2009. In this capacity, she led DOD policy and strategy to prevent WMD proliferation and use, reduce and eliminate WMD risks and respond to WMD dangers. She was a key leader on issues ranging from the elimination of Syria’s chemical weapons, nuclear response and mitigation during the Fukushima crisis, and WMD interdiction policy and response. Ms. Hersman led DoD engagements on WMD issues with NATO, the Republic of Korea, Japan, and others, and also served as DOD’s principal policy advocate on WMD arms control, nonproliferation and threat reduction. Prior to joining DOD, Ms. Hersman was a senior research fellow with the Center for the Study of Weapons of Mass Destruction at the National Defense University from 1998 to 2009. Ms. Hersman previously held positions as an international affairs fellow at the Council on Foreign Relations, a special assistant to the undersecretary of defense for policy, and a member of the House Armed Services Committee professional staff. She holds an M.A. in Arab studies from Georgetown University and a B.A. from Duke University.

Join us for a seminar with Dr. Kim Knight, Staff Scientist at the Lawrence Livermore National Laboratory, titled “Understanding the Influence of Environment on Nuclear Explosion Physics and Chemistry.”

The seminar will begin at 3pm ET on April 6, 2021. It will be held via Microsoft Teams.

Abstract: With the explosion of the world’s first nuclear test, Trinity, in 1945, the formation of post-detonation debris (‘fallout’) became a topic of study and research. Initial interest in the glassy materials produced from near-surface nuclear events centered around study of formation mechanisms, as well as a drive to understand dispersion of debris and its contribution as a radiological hazard. As above ground nuclear testing dwindled in the late 1960’s, however, this area of research all but disappeared. Changing perceptions of nuclear threats and concerns over nuclear effects have brought about a resurgence of interest to improve our understanding of how fireballs evolve, the conditions under which fallout forms, and how physical and chemical processes can be perturbed by local explosion conditions. I will review recent contributions aimed at furthering our modern understanding of the interaction of the local environment with a nuclear explosion including the formation of fallout and work to understand when and how the local explosion environment may influence the evolution of a nuclear explosion.

Speaker Bio: As staff at Lawrence Livermore National Laboratory for over a decade, Kim Knight’s primary role has been coordination and execution of the forensic analysis of radioactive and nuclear materials in support of national security and related research. Prior to joining LLNL, she completed a PhD at the University of California, Berkeley as a geochemist specializing in application of radioactive decay systems to understand earth systems processes. Later she transitioned to The University of Chicago, developing methods for measuring nucleosynthetic signatures in trace amounts of stellar dust and early solar system materials. Her past and present work provide unique insight into the identification, handling, and coordinated characterization of material samples by diverse technical methods to interpret material signatures and she is a recognized resource for challenging samples and complex scenarios. In addition to programmatic work, her research and vision have been instrumental to the modern renaissance in study of post-detonation debris to advance environmental considerations, weapons science, post-detonation forensics, and related applications.

Join us for a seminar with Dr. Laura Berzak Hopkins, Design Physicist at the Lawrence Livermore National Laboratory, titled “X-ray:matter interaction experiments at the National Ignition Facility.”

The seminar will begin at 3pm ET on Tuesday, March 2, 2021. It will be held via Microsoft Teams.

Abstract: There is a growing number of objects orbiting in exo-atmospheric environments with the potential to be exposed to damaging radiation. These objects tend to be both expensive and important components of transportation and communication infrastructure, and therefore, assuring these sensitive objects are survivable in this potentially hostile environment is of high importance. A family of targets has been developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory that is imploded by the NIF’s 192 lasers to generate bright sources of X-rays. Advanced fielding hardware allows samples to be placed near these X-ray sources, and in-situ diagnostics measure time-resolved response. We implement this experimental capability to collect data on X-ray:sample interaction, including impulsive response with post-shot sample inspection and assessment. Data is then utilized to validate the functionality of our radiation-hydrodynamics simulations which are utilized to predict response and assess the survivability of exo-atomspheric objects of interest.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Speaker Bio: Dr. Laura Berzak Hopkins is a design physicist at Lawrence Livermore National Laboratory and the Physics Lead for the Livermore Survivability Program. Previously, she was the lead designer for the Inertial Confinement Fusion (ICF) High-Density Carbon (HDC) Integrated Experiments Campaign, which achieved the NNSA alpha-heating milestone with record NIF neutron yield and stagnation pressures. Her work on NIF has included development of low gas-fill density hohlraums and implosion control with laser pulse shaping as well as a gaseous radiochemistry diagnostic. She studied Physics and Chemistry for her undergraduate degree from Dartmouth College. Her graduate degree is in Plasma Physics from Princeton University where she was an NNSA Stockpile Stewardship Graduate Fellow. Before joining Livermore, Laura served as a Congressional Fellow in the U.S. House of Representatives and then the U.S. Senate advising on arms control policy and environmental regulations. 

Join us for a seminar with Dr. Carolyn C. Kuranz, Associate Research Scientist at the University of Michigan, titled “Hydrodynamic Instability and Radiation Hydrodynamics Experiments in High-energy-density Plasmas.”

The seminar will begin at 3pm ET on February 2, 2021. It will be held via Microsoft Teams.

Abstract: Hydrodynamic instabilities can occur during multiple phases of inertial confinement fusion experiments causing unwanted hydrodynamic mixing, limiting gain and stymie fusion ignition. Therefore, it is important to fundamentally understand these instabilities through experiments, simulations, and theory. Using high-energy lasers, we can create strong pressure and velocity gradients that drive hydrodynamic instabilities under high-energy-density conditions. Also, strong radiation fields can affect hydrodynamic evolution. I will present a study of the evolution of hydrodynamic instabilities and radiative shocks, specifically the suppression of Kelvin-Helmholtz growth due to compressible effects, and the ablative stabilization of the Rayleigh-Taylor instability. We use the x-ray radiography technique to create a 2D image of instability growth and observe the evolution of these processes.

This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0002956, and the National Laser User Facility Program, grant number DE-NA0002719, and National Science Foundation through the Basic Plasma Science and Engineering program NSF 16-564, grant number 1707260.

Speaker Bio: Dr. Carolyn Kuranz graduated with honors in Physics from Bryn Mawr College in 2002 and earned her PhD in Applied Physics from University of Michigan in 2009. She is currently an Associate Research Scientist at the University of Michigan and a Primary Investigator of a National Nuclear Security Association Center of Excellence, the Center for Laboratory Astrophysics. Dr. Kuranz has led high-energy-density physics experiments at facilities around the world studying hydrodynamic instabilities, radiation hydrodynamics, and magnetohydrodynamics. She is an ex officio Executive Committee of the Division of Plasma Physics of the American Physical Society and received University of Michigan’s Ted Kennedy Family Faculty Team Excellence Award for her participation in the Center for Radiative Shock Hydrodynamics.