C. A. Thomas
A5051880855- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Combustion and Detonation Processes
- Laser Design and Applications
- Cold Fusion and Nuclear Reactions
- Magnetic confinement fusion research
- Fusion materials and technologies
- Energetic Materials and Combustion
- Traumatic Ocular and Foreign Body Injuries
- Engineering and Material Science Research
- Cold Atom Physics and Bose-Einstein Condensates
- Solid State Laser Technologies
- Advanced Optical Sensing Technologies
- Advanced Chemical Physics Studies
- Ion-surface interactions and analysis
- Ocular and Laser Science Research
- Nonlinear Optical Materials Research
- Advanced X-ray Imaging Techniques
- Computational Fluid Dynamics and Aerodynamics
- Atomic and Subatomic Physics Research
- Photorefractive and Nonlinear Optics
Applied Energetics (United States)
2012-2025
University of Rochester
2012-2024
Energetics (United States)
2012-2024
Lawrence Livermore National Laboratory
2011-2020
Los Alamos National Laboratory
2010-2020
General Atomics (United States)
2010-2020
Diamond Materials (Germany)
2018-2020
Atomic Weapons Establishment
2012-2020
Massachusetts Institute of Technology
2012-2018
Fusion Academy
2012-2014
Point design targets have been specified for the initial ignition campaign on National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)]. The contain D-T fusion fuel in an ablator of either CH with Ge doping, or Be Cu. These shells are imploded a U Au hohlraum peak radiation temperature set between 270 300 eV. Considerations determining point include laser-plasma interactions, hydrodynamic instabilities, laser operations, target fabrication....
Radiative hydrodynamics simulations of ignition experiments show that energy transfer between crossing laser beams allows tuning the implosion symmetry. A new full-scale, three-dimensional quantitative model has been developed for crossed-beam transfer, allowing calculations propagation and coupling multiple their associated plasma waves in hohlraums. This implemented a radiative-hydrodynamics code, demonstrating control symmetry by wavelength separation cones beams.
An inertial fusion implosion on the National Ignition Facility, conducted August 8, 2021 (N210808), recently produced more than a megajoule of yield and passed Lawson's criterion for ignition [Phys. Rev. Lett. 129, 075001 (2022)]. We describe experimental improvements that enabled N210808 present first measurements from an igniting plasma in laboratory. metrics like product hot-spot energy pressure squared, absence self-heating, increased by ∼35%, leading to record values enhancement...
We present the design of first igniting fusion plasma in laboratory by Lawson's criterion that produced 1.37 MJ energy, Hybrid-E experiment N210808 (August 8, 2021) [Phys. Rev. Lett. 129, 075001 (2022)10.1103/PhysRevLett.129.075001]. This uses indirect drive inertial confinement approach to heat and compress a central "hot spot" deuterium-tritium (DT) fuel using surrounding dense DT piston. Ignition occurs when heating from absorption α particles created process overcomes loss mechanisms...
The crystal structure, refractive indices, and phase-matching conditions for a new nonlinear optical material, L-histidine tetrafluoroborate (HFB), are reported. HFB grows readily, displays favorable mechanical characteristics, has adequate birefringence to permit phase-matched parametric processes over much of its transparency range (250 nm 1300 nm). loci angular sensitivity second-harmonic generation 1064-nm light in single crystals were measured. effective nonlinearity is comparable with...
Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase probability of ignition. The experimentally correct for residual uncertainties in implosion hohlraum physics used our radiation-hydrodynamic computational models using a variety ignition capsule surrogates before proceeding cryogenic-layered implosions experiments. quantitative goals technique...
The recently completed National Ignition Campaign (NIC) on the Facility (NIF) showed significant discrepancies between post-shot simulations of implosion performance and experimentally measured performance, particularly in thermonuclear yield. This discrepancy simulation observation persisted despite concerted efforts to include all known sources degradation within a reasonable two-dimensional (2-D), even three-dimensional (3-D), model, e.g., using surface imperfections radiation drives...
High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results thinner with larger inner radius given capsule scale. This leads to absorption and shorter laser pulses compared equivalent CH designs. paper will describe series of experiments carried out examine the feasibility using both gas filled hohlraums lower density,...
Capsule implosions on the National Ignition Facility (NIF) [Lindl et al., Phys. Plasmas 11, 339 (2004)] are underway with goal of compressing deuterium-tritium (DT) fuel to a sufficiently high areal density (ρR) sustain self-propagating burn wave required for fusion power gain greater than unity. These driven carefully tailored sequence four shock waves that must be timed very precision in order keep DT low adiabat. Initial experiments measure strength and relative timing these shocks have...
The first series of experiments the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] tested ignition Hohlraum “energetics,” a term described by four broad goals: (1) measurement laser absorption Hohlraum; (2) x-ray radiation flux (TRAD4) on surrogate capsule; (3) quantitative understanding and resultant flux; (4) determining whether initial performance is consistent with requirements for ignition. This paper summarizes status NIF energetics experiments....
Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This made possible by using dense ablator (high-density carbon), which shortens drive duration needed to achieve convergence: measured 40% higher efficiency than typical gas-filled hohlraums, requires less laser...
The locus of National Ignition Facility (NIF) inertial confinement fusion (ICF) implosion data, in hot-spot burn-average areal density (ρR) and Brysk temperature (T) space, is shown illustrates that several implosions are nearing a burning plasma state, where α-heating the dominant source heating. A formula for diagnosing using measured/inferred data from ICF experiments given with underlying derivation. Plotting performance against inferred energy key need to maximize delivery an hot-spot....
The Bigfoot approach is to intentionally trade off high convergence, and therefore areal-density, in favor of implosion velocity good coupling between the laser, hohlraum, shell, hotspot. This results a short laser pulse that improves hohlraum symmetry predictability, while reduced compression reduces hydrodynamic instability growth. thus far include demonstrated low-mode control at two different geometries (5.75 mm 5.4 diameters) target scales (5.4 6.0 spanning 300–405 TW power 0.8–1.6 MJ...
We present a data-based model for low mode asymmetry in gas-fill hohlraum experiments on the National Ignition Facility {NIF [Moses et al., Fusion Sci. Technol. 69, 1 (2016)]} laser. This is based hypothesis that these fill hohlraums dominated by hydrodynamics of expanding, density, high-Z (gold or uranium) “bubble,” which occurs where intense outer cone laser beams hit wall. developed simple states implosion symmetry becomes more oblate as bubble size large compared to radius capsule...
To reach the pressures and densities required for ignition, it may be necessary to develop an approach design that makes easier simulations guide experiments. Here, we report on a new short-pulse inertial confinement fusion platform is specifically designed more predictable. The has demonstrated $99%+0.5%$ laser coupling into hohlraum, high implosion velocity ($411\text{ }\text{ }\mathrm{km}/\mathrm{s}$), hotspot pressure ($220+60\text{ }\mathrm{Gbar}$), cold fuel areal density compression...
The full scale modeling of power transfer between laser beams crossing in plasmas is presented. A new model was developed, allowing calculations the propagation and coupling pairs with their associated plasma wave three dimensions. complete set beam smoothing techniques used ignition experiments modeled effects on crossed-beam energy are investigated. shift wavelength can move instability or out resonance hence allows tuning transfer. effective pointing symmetry have been Several designs...
A series of 40 experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] to study energy balance and implosion symmetry in reduced- full-scale ignition hohlraums was shot at energies up 1.3 MJ. This paper reports findings analysis ensemble experimental data obtained that has produced an improved model for simulating hohlraums. Last year first observation a NIF hohlraum transfer between cones beams as function wavelength shift those reported [P....
Herein, recent progress on indirectly-driven inertial confinement fusion (ICF) work at the National Ignition Facility (NIF) is briefly reviewed. An analytic criteria for an ICF burning plasma given and compared to implosion data from NIF. Scaling of key hot-spot performance metrics derived simple physics considerations, including some speculative impacts asymmetry assembly disassembly implosion. A steepest descent solution nonlinear equation pressure peak compression, with full effects...
For several years, we have been calculating the radiation drive in laser-heated gold hohlraums using flux-limited heat transport with a limiter of 0.15, tabulated values local thermodynamic equilibrium opacity, and an approximate model for not (NLTE) emissivity (DCA_2010). This has successful predicting vacuum hohlraums, but gas-filled used to capsule implosions, consistently predicts too much bang times earlier than measured. In this work, introduce new that brings calculated time into...
Advances in hohlraums for inertial confinement fusion at the National Ignition Facility (NIF) were made this past year hohlraum efficiency, dynamic shape control, and hot electron x-ray preheat control. Recent experiments are exploring behavior over a large landscape of parameters by changing shape, gas-fill, laser pulse. Radiation hydrodynamic modeling, which uses measured backscatter, shows that gas-filled utilize between 60% 75% power to match bang-time, whereas near-vacuum 98%....
Mix of high-Z material from the capsule into fuel can severely degrade performance inertial fusion implosions. On Hybrid B campaign, testing largest high-density-carbon capsules yet fielded at National Ignition Facility, several shots show signatures high levels hot-spot mix. We attribute a ∼40% yield degradation on these to mix, comparable level large P2 asymmetries observed some shots. A range instability growth factors and diamond crystallinity were tested they do not determine mix for...
High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows ignition designs with laser pulse durations of <10 ns. A series Inertial Confinement Fusion (ICF) experiments 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated deuterium-tritium (DT) layered implosion driven by 6.8 ns, 2-shock pulse. This paper describes these and comparisons ICF design code simulations. Backlit...