A5025712831- Laser-Plasma Interactions and Diagnostics
- High-pressure geophysics and materials
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Diamond and Carbon-based Materials Research
- Laser Design and Applications
- Laser Material Processing Techniques
- Laser-Matter Interactions and Applications
- Plasma Diagnostics and Applications
- Ion-surface interactions and analysis
- Particle Dynamics in Fluid Flows
- Scientific Measurement and Uncertainty Evaluation
- Advanced X-ray Imaging Techniques
- Geophysics and Sensor Technology
- Geological and Geochemical Analysis
- Chaos control and synchronization
- Cellular and Composite Structures
- Fluid Dynamics and Turbulent Flows
- Planetary Science and Exploration
- X-ray Spectroscopy and Fluorescence Analysis
- Energetic Materials and Combustion
- Tribology and Lubrication Engineering
- Advanced Materials and Mechanics
- Nuclear Materials and Properties
- High-Velocity Impact and Material Behavior
Lawrence Livermore National Laboratory
2018-2025
University of California, Berkeley
2015-2022
Atomic Weapons Establishment
2021
University of Rochester
2019-2020
Energetics (United States)
2019-2020
ELI-HU Research and Development Non-Profit
2019
The University of Texas at Austin
2019
University of California, Los Angeles
2019
SLAC National Accelerator Laboratory
2019
Lawrence Berkeley National Laboratory
2017-2018
We investigate a new regime for betatron x-ray emission that utilizes kilojoule-class picosecond lasers to drive wakes in plasmas. When such laser pulses with intensities of ∼5×10^{18} W/cm^{2} are focused into plasmas electron densities ∼1×10^{19} cm^{-3}, they undergo self-modulation and channeling, which accelerates electrons up 200 MeV energies causes those emit x rays. The measured spectra fit synchrotron spectrum critical energy 10-20 keV, 2D particle-in-cell simulations were used...
Recent experiments of laser-driven ejecta microjets performed at OMEGA 60 reveal tortuous jets whereby the appear to deviate from their initial trajectory as they travel in vacuum. To understand these data, we perform two dimensional numerical simulations, considering different target thicknesses, pressures, and models drive conditions. In particular, modeling finite laser spot size appears essential reproducing qualitatively non-planar shock observed experiment. Simulations capture jet...
Abstract The gas and ice giants in our solar system can be seen as a natural laboratory for the physics of highly compressed matter at temperatures up to thousands kelvins. In turn, understanding their structure evolution depends critically on ability model such matter. One key aspect is miscibility elements interiors. Here, we demonstrate feasibility X-ray Thomson scattering quantify degree species separation 1:1 carbon–hydrogen mixture pressure ~150 GPa temperature ~5000 K. Our...
We have developed an experimental platform at the National Ignition Facility that employs colliding planar shocks to produce warm dense matter with uniform conditions and enable high-precision equation of state measurements. The uses simultaneous x-ray Thomson scattering radiography measure density, electron temperature, ionization in matter. is designed create a large volume plasma (approximately 700×700×150μm3) pressures approaching 100 Mbar minimize distribution volume, significantly...
Diamond formation in polystyrene (C8H8)n, which is laser-compressed and heated to conditions around 150 GPa 5000 K, has recently been demonstrated the laboratory [Kraus et al., Nat. Astron. 1, 606–611 (2017)]. Here, we show an extended analysis comparison first-principles simulations of acquired data their implications for planetary physics inertial confinement fusion. Moreover, discuss advanced diagnostic capabilities adding high-quality small angle X-ray scattering spectrally resolved...
Laser-plasma-based accelerators are now able to provide the scientific community with novel high-energy light sources that essential study density matter, inertial confinement fusion, astrophysical systems, and fundamental plasma physics. Due transient high-density properties of these it is develop in hard x-ray energy range (0.01–1 MeV) directional have high yield, low divergence, short duration (ps sub-ps). In this work, we show by using a Laser accelerator, possible generate broadband...
Abstract We investigated the high-pressure behavior of polyethylene (CH 2 ) by probing dynamically-compressed samples with X-ray diffraction. At pressures up to 200 GPa, comparable those present inside icy giant planets (Uranus, Neptune), shock-compressed retains a polymer crystal structure, from which we infer presence significant covalent bonding. The A /m structure observe has previously been seen at significantly lower pressures, and equation state measured agrees our findings. This...
This paper presents an experimental and theoretical study of betatron x-ray radiation from laser wakefield acceleration in the self-modulated regime. Our experiments use picosecond duration pulses up to 150 J, for plasmas with electronic densities on order 1019 cm−3. In regime, electrons accelerated wake pulse are subject both longitudinal plasma transverse electrical fields. As a result, they undergo oscillations radiate synchrotron-like spectrum. our configuration, about 300 MeV, as well...
Abstract We present structure and equation of state (EOS) measurements biaxially orientated polyethylene terephthalate (PET, $$({\hbox {C}}_{10} {\hbox {H}}_8 {O}}_4)_n$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mo>(</mml:mo> <mml:mtext>C</mml:mtext> <mml:mn>10</mml:mn> </mml:msub> <mml:mtext>H</mml:mtext> <mml:mn>8</mml:mn> <mml:mtext>O</mml:mtext> <mml:mn>4</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mi>n</mml:mi> </mml:math> , also called...
X-ray Thomson scattering (XRTS) is a powerful diagnostic technique that involves an x-ray source interacting with dense plasma sample, resulting in spectrum of elastically and inelastically scattered x-rays. Depending on the conditions, one can measure range parameters from spectrum, including temperature, electron density, ionization state. To achieve sensitivity to collective oscillations, XRTS measurements require limited momentum transfer where spectral separation elastic inelastic...
The study of high-velocity particle-laden flow interactions is importance for the understanding a wide range natural phenomena, ranging from planetary formation to cloud interactions. Experimental observations particle dynamics are sparse given difficulty generating flows many particles. Ejecta microjets micron-scale jets formed by strong shocks interacting with imprinted surfaces generate plumes traveling at several kilometers per second. As such, interaction two ejecta provides novel...
We present results for the ionic structure in hydrocarbons (polystyrene, polyethylene) that were shock compressed to pressures of up 190 GPa, inducing rapid melting samples. The resulting liquid is then probed using situ diffraction by an x-ray free electron laser beam, demonstrating capability obtain reliable data a single shot, even low-Z samples without long range order. agree well with ab initio simulations, validating ability such approaches model mixed states where complex...
We present a new experimental platform to perform spectrally resolved x-ray scattering measurements of ionization, density and temperature in imploding CH or beryllium capsules at the National Ignition Facility. Scattered x-rays 9 keV from zinc He-alpha plasma source angle 120 degrees are highly sensitive K-shell while same time constraining temperature. This will allow for studies dense plasmas with free electron densities up 1025 cm-3 giving possibility investigate effects pressure...
We present measurements of the nucleation rate into a diamond lattice in dynamically compressed polystyrene obtained pump-probe experiment using high-energy laser system and situ femtosecond x-ray diffraction. Different temperature-pressure conditions that occur planetary interiors were probed. For single shock reaching 70 GPa 3000 K no formation was observed, while with double driving to pressures around 150 temperatures 5000 rates between ${10}^{29}$...
A comparative experimental study of betatron x-ray radiation from laser wakefield acceleration in the blowout and self-modulated regimes is presented. Our experiments use picosecond duration pulses up to 150 J (self-modulated regime) 60 fs 10 (blowout regime), for plasmas with electronic densities on order 1019 cm−3. In regime, where has been very little studied compared electrons accelerated wake pulse are subject both longitudinal plasma transverse electrical fields. As a result, their...
Understanding dynamic fragmentation in shock-loaded metals and predicting properties of the resulting ejecta are considerable importance for both basic applied science. The nature material ejection has been shown to change drastically when free surface melts on compression or release. In this work, we present hydrodynamic simulations laser-driven microjetting from micron-scale grooves a tin surface. We study microjet formation across range shock strengths drives that leave target solid after...
Ejecta microjets offer an experimental methodology to study high-speed particle laden-flow interactions, as consist of millions particulates traveling at velocities several kilometers per second and are easily generated by most common shock drives. Previous experiments on the OMEGA Extended Performance laser found that collisions between two counter-propagating laser-driven tin ejecta varied a function drive pressure; jets near pressures 10 GPa passed through each other without interacting,...
This paper presents results of x-ray Thomson scattering on a plasma in the warm dense matter regime. The experiment generates uniform sample with long duration time, which represents an advance experimental studies this analysis also reveals shortcomings previous theoretical approaches and shows that technique is suitable for measuring relevant conditions.
Understanding ejecta interactions is broadly relevant to understanding debris shielding and materials physics. The literature contains many examples of experiments that examine generation from high explosive gas gun sources, but there exist very few laser-driven experiments. To end, we present initial measurements on the OMEGA OMEGA-EP laser facilities seek develop platforms characterize mass-velocity distributions driven ejecta, with end goal using power lasers study ejecta-ejecta...
Abstract This work presents first insights into the dynamics of free-surface release clouds from dynamically compressed polystyrene and pyrolytic graphite at pressures up to 200 GPa, where they transform diamond or lonsdaleite, respectively. These ejecta are released either vacuum various types catcher systems, monitored with high-speed recordings (frame rates 10 MHz). Molecular simulations used give rate preservation throughout free expansion impact process, highlighting challenges...