Physics

Group leader: John Klepeis

We research theoretical and computational condensed-matter physics in support of major Department of Energy and LLNL programs. Our research emphasizes quantum mechanical modeling and simulation of materials properties over wide ranges of temperature and pressure, focusing on understanding and elaborating the structural and thermodynamic properties of metals.

To learn more about our research, methods, and staff, visit the EOS and Materials Theory Group page.

Group leader: Damian Swift

We develop and implement new tools for EOS and related applications. Our work spans from quantum electronic structure code development to the libleos application program interface and associated tools. Our goal is to emphasize the importance of longer-term capability development for EOS-related activities.

Group leader: Christine Wu

The Equation of State (EOS) and Program Integration group seeks to bridge state-of-the-art science with mission-critical programmatic needs, including high-pressure inertial confinement fusion applications and planetary science. One of our key goals is to deliver physics-based equations of states for a wide range of materials including metals, compounds, and molecular systems—as well as mixtures of such material—in order to accurately describe the thermodynamic behavior under compression and heating in hydrodynamic simulations.

To achieve this, we:

• Develop EOS free-energy models, mixture algorithms, and uncertainty quantification methodologies, all of which are being continually improved for implementation into our EOS generation codes.
• Incorporate state-of-the-art experiments through engagements with our colleagues in the static and dynamic high-pressure communities.
• Design and conduct application-relevant ab initio quantum calculations in collaboration with other groups in the Condensed Matter section and incorporate these calculations into the construction of our EOS models.
• Maintain a close integration with programmatic applications and scientific efforts on other constitutive models that rely on EOS information, such as the ongoing efforts to develop strength and phase-transition-kinetics models.

Group leader: Zsolt Jenei          

We are an experimental group focused on studying materials under extreme high-pressure and temperature conditions. We develop advanced compression capabilities using the diamond anvil cell and advanced x-ray and optical diagnostics. The group carries out high-fidelity experiments to determine physical, thermodynamic, and constitutive properties of materials. Our research directly aligns with the shared stockpile stewardship mission of LLNL and the National Nuclear Security Administration. 

Group leader: Minta Akin         

Our group uses dynamic compression to study materials under extreme compression and thermal conditions. We conduct high-fidelity, high-precision studies of the physical, thermodynamic, and constitutive properties of matter and the associated dynamics and kinetics of phase transitions using a combination of experimental platforms (gas guns, lasers, beamlines, etc.). We also develop novel diagnostics, statistical models, and analysis packages to support this work. Our experimental studies vitally affect and are closely aligned to the National Nuclear Security Administration’s stockpile stewardship mission.

Group leader: Yaniv Rosen

Our group is focused on development of hardware, algorithms, and control for near-term applications in quantum information, sensing, and computing. Overarching goals are to draw from and build a community around intersections in applied mathematics, computer science, quantum information, and device physics to make optimal use of near-term quantum hardware.

To learn more about our research and facilities, visit the Quantum Coherent Device Physics Group page.

Group leader: Alfredo Correa-Tedesco

Associate Program Leader: Jason Sears (Acting)

Group leader: Tammy Ma

The Inertial Fusion Energy (IFE) team at LLNL supports the Department of Energy’s Office of Science Fusion Energy Sciences efforts to advance inertial confinement fusion as an energy source for societal needs. As home to the National Ignition Facility and the Jupiter Laser Facility, LLNL is connected to unique capabilities in this area and now leads a national IFE effort that encompasses many needed advancements, including more efficient and repetitive-firing laser drivers and new target designs that will be needed to adopt this technology for practical use.

High Energy Density Laboratory Plasmas supports fundamental science to explore matter at extreme conditions of temperature, density, and pressure. This includes wide-ranging areas from laboratory astrophysics and planetary science to the structure and dynamics of matter at atomic scales. Our scientists probe the physics of laser-plasma interactions and study the structure of magnetized plasmas.  We both use and support the LaserNetUS network and the Matter for Extreme Conditions end station at SLAC National Accelerator Laboratory.

Group leader: Steve Allen

We compare experimental results with analytical theory and computational models of plasma behavior to develop novel diagnostic measurements and execute state-of-the-art MFE experiments focused on both the core and boundary of high-performance MFE plasmas. Our advanced diagnostics are relevant to one of the most ambitious energy projects in the world, ITER. We focus specifically on experiments conducted at the DIII-D National Fusion Facility at General Atomics.

Group leader: Ben Dudson

Our group undertakes basic and applied plasma science as well as plasma theory and computations in support of magnetic and inertial fusion experiments. Our researchers develop fluid and kinetic plasma models and work with applied mathematicians and computer scientists to develop advanced algorithms that utilize high performance computing to simulate plasma phenomena.

One of the focus areas of our group is understanding and controlling the boundary region of magnetically confined plasmas: A transition region between hot confined plasma and the walls of the surrounding vessel that is critical to fusion performance. To do this, we have developed expertise in plasma physics, atomic and molecular physics, plasma-wall interactions, and maintain strong links to engineering groups and experimental teams.

Simulation tools developed in our group with domestic and international partners include the UEDGE plasma transport solver, the BOUT++ framework for writing fluid plasma simulations in curvilinear geometry, and the COGENT continuum kinetic code.

Group leader: Vlad Soukhanovskii

We compare experimental results with analytical theory and computational models of plasma behavior to develop novel diagnostic measurements and execute state-of-the-art magnetic fusion energy (MFE) experiments focused on both the core and boundary of high-performance MFE plasmas. Our advanced diagnostics are relevant to one of the most ambitious energy projects in the world, ITER. 

We focus specifically on experiments conducted at Princeton Plasma Physics Laboratory’s National Spherical Torus Experiment Upgrade (NSTX-U) and Lithium Tokamak Experiment-Beta, in addition to the Mega-Ampere Spherical Tokamak Upgrade at the Culham Centre for Fusion Energy in the United Kingdom.

Group leader: Andrea Schmidt

Group leader: Alison Saunders

We focus on the study of high energy density material properties in support of a broad swath of LLNL-relevant missions. Specifically, we study materials using a myriad of dynamic compression facilities, ranging from gas guns to lasers, in order to understand how materials compress, stretch, and fail under extreme conditions. Our work supports both fundamental understanding of how material behavior changes at high pressure conditions, as well as focused studies to improve material models and enhance laboratory simulation capabilities.  

Group leader: Andy Krygier

The Dynamic Compression of Materials group performs experiments investigating material properties at extreme compression. We use both laser and gas-gun drivers to shock or ramp compress solids, liquids, gases, and plasma to the multi-millibar pressure regime and beyond. Our physics experiments target fundamental high-pressure science questions relevant to complex systems like alloys and compounds, high pressure chemistry, the interiors of large planets, and inertial confinement fusion conditions. We reach ‘beyond current boundaries’ by innovating new approaches and reimagining existing capabilities. We are fundamentally driven by discovery that is underpinned by an unwavering dedication to excellence, rigorousness, and transparency.

Group leader: Yuan Ping

We develop and use dynamic compression techniques and advanced diagnostics to explore the behavior of matter at millions to billions of atmospheres pressures, conditions exceeding the atomic unit of pressure (~100 million atmospheres), and to reproduce states existing deep inside stars, sub-stellar objects, and planets. This fundamental research is giving a new understanding to core shell chemistry, the behavior of solids at high pressures, the evolution of planets, the potential for controlled thermonuclear plasmas, and a wide variety of national security applications.

Group leader: Robert Heeter

We study the radiation properties of plasmas and the effects of x-rays on materials and systems. These properties include the basic atomic physics of isolated ions, opacities and radiation flow in hot dense matter, photoionization in black hole accretion disks, and x-ray spectra emitted by ignited fusion plasmas. The plasmas in these experiments are produced at laser facilities such as the National Ignition Facility and the Jupiter Laser Facility, as well as using devices like the Electron Beam Ion Trap.

Group leader: Steve Libby

Our primary focus is on understanding and computing the microscopic physics of hot and warm dense plasmas, with typical applications to laser-produced plasmas, intense laser–matter interaction, inertial fusion, stockpile stewardship, and astrophysics. To do this, we develop and apply cutting-edge theoretical and computational models to electron relativistic and non-relativistic atomic physics, the equilibrium and non-equilibrium statistical physics of dense hot dense plasmas, radiation opacities, plasma equations of state, transport, and laser-plasma interaction.

We use our models to produce the detailed opacities and plasma equations of state required for radiation-hydrodynamics simulations. For example, the OPAL opacity code—now a key part of the standard solar model—was developed in our group. In parallel, we also apply our computational techniques to work with our experimental teams on the development and analysis of experiments aimed at probing the physics of inertial fusion and other plasmas, including understanding the impact of high magnetic fields, developing specialty hard x-ray sources, and advancing the physics of short-pulse, laser-driven high harmonics. In addition to traditional atomic physics methods, we are also applying Bayesian inference techniques and machine learning methods in these areas.

Lastly, we work on the development of quantum coherent sensors based on atom interferometry for security and basic science applications, as well as the development of ion trap quantum computing.

Group leaders: Bernard Kozioziemski (imaging) and Sabrina Nagel (detection)

Our Imaging and Detection groups develop and deploy advanced x-ray diagnostics and measurement techniques at the National Ignition Facility (NIF). Measurements with x-rays provide a unique view of many processes in the high-energy-density (HED) sciences. Dense plasmas and dense metals are often opaque to visible light, but transparent to x-rays, making x-rays a good characterization tool for HED measurements. Many materials will also begin to emit x-rays when they reach extreme temperatures, such as those achieved during inertial confinement fusion (ICF) experiments.

We work on pushing both spatial and temporal resolutions, developing x-ray diagnostics capable of resolving features one-tenth the size of a human hair in fractions of a nano-second. These diagnostics include particle spectrometers, x-ray optics for imaging, ultra-fast x-ray detectors, and high-efficiency detection. These measurements must be acquired while operating in the harsh NIF environment, which is bathed in electromagnetic interference and potentially neutrons.

Other areas of exploration include the development of bright laser-produced x-ray sources, image analysis methods to quantify material shape during ICF implosions, and the development of new experiments to understand HED physics.