M. J. MacDonald
A5047091636- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Diamond and Carbon-based Materials Research
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Laser-Matter Interactions and Applications
- Solar and Space Plasma Dynamics
- Building Energy and Comfort Optimization
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pancreatic function and diabetes
- Ion-surface interactions and analysis
- Geological and Geochemical Analysis
- Plasma Diagnostics and Applications
- Facilities and Workplace Management
- Mass Spectrometry Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- X-ray Diffraction in Crystallography
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Laser Design and Applications
Lawrence Livermore National Laboratory
2015-2025
University of California, Berkeley
1996-2024
University of Michigan–Ann Arbor
2014-2023
SLAC National Accelerator Laboratory
2014-2022
Stanford University
2014-2022
University of Wisconsin–Madison
1989-2021
Menlo School
2016-2020
Nationwide Children's Hospital
2019
The Ohio State University
2019
University of Rochester
2018
Abstract Obtaining a burning plasma is critical step towards self-sustaining fusion energy 1 . A one in which the reactions themselves are primary source of heating plasma, necessary to sustain and propagate burn, enabling high gain. After decades research, here we achieve burning-plasma state laboratory. These experiments were conducted at US National Ignition Facility, laser facility delivering up 1.9 megajoules pulses with peak powers 500 terawatts. We use lasers generate X-rays radiation...
Abstract In a burning plasma state 1–7 , alpha particles from deuterium–tritium fusion reactions redeposit their energy and are the dominant source of heating. This has recently been achieved at US National Ignition Facility 8 using indirect-drive inertial-confinement fusion. Our experiments use laser-generated radiation-filled cavity (a hohlraum) to spherically implode capsules containing deuterium tritium fuel in central hot spot where occur. We have developed more efficient hohlraums...
We report electrical conductance and thermopower measurements on InAs nanowires synthesized by chemical vapor deposition. Gate modulation of the individual with diameter around 20nm is obtained over T=40 to 300K. At low temperatures (T< ~100K), oscillations in power factor concomitant stepwise increases are observed as gate voltage shifts potential electrons nanowire through quasi-one-dimensional (1D) sub-bands. This work experimentally shows possibility modulate semiconductor nanowire's...
The matter in extreme conditions end station at the Linac Coherent Light Source (LCLS) is a new tool enabling accurate pump–probe measurements for studying physical properties of high-energy density (HED) physics regime. This instrument combines world's brightest x-ray source, LCLS beam, with high-power lasers consisting two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These produce short-lived states high pressures, temperatures or densities that are important...
Abstract We present a formally exact and simulation-free approach for the normalization of X-ray Thomson scattering (XRTS) spectra based on f-sum rule imaginary-time correlation function (ITCF). Our method works any degree collectivity, over broad range temperatures, is applicable even in nonequilibrium situations. In addition to giving us model-free access electronic correlations, this new opens up intriguing possibility extract plethora physical properties from ITCF XRTS experiments.
Abstract Indirect Drive Inertial Confinement Fusion Experiments on the National Ignition Facility (NIF) have achieved a burning plasma state with neutron yields exceeding 170 kJ, roughly 3 times prior record and necessary stage for igniting plasmas. The results are despite multiple sources of degradations that lead to high variability in performance. Results shown here, first time, include an empirical correction factor mode-2 asymmetry regime addition previously determined corrections...
JOHANNES Kepler is famous for discovering the laws of planetary motion, but he less well known writing what may have been first science-fiction story to involve space travel. During his observations, German astronomer noticed that tails comets always point away from Sun, which suggested Sun was exerting a sort radiant pressure. This led him in 1609 – year published propose sailing Earth Moon on light itself. Of course, and still stuff science fiction, 400 years later Kepler's initial ideas...
We report experimental evidence that multi-MeV protons accelerated in relativistic laser-plasma interactions are modulated by strong filamentary electromagnetic fields. Modulations observed when a preplasma is developed on the rear side of $\ensuremath{\mu}\mathrm{m}$-scale solid-density hydrogen target. Under such conditions, fields amplified electron Weibel instability and maximized at critical density region The analysis spatial profile indicates generation $B>10\text{ }\text{...
Significance Magnetic fields exist throughout the universe. Their energy density is comparable to of fluid motions plasma in which they are embedded, making magnetic essential players dynamics luminous matter The origin and amplification these their observed strengths far from being understood. standard model for galactic intergalactic through seed via turbulent processes level consistent with current observations. For this process be effective, needs reach a strongly nonlinear phase....
We report on a high repetition rate proton source produced by high-intensity laser irradiation of continuously flowing, cryogenic hydrogen jet. The energy spectra are recorded at 1 Hz for Draco powers 6, 20, 40, and 100 TW. delivers ∼1013 protons/MeV/sr/min. find that the average number over one minute, energies sufficiently far from cut-off energy, is robust to laser-target overlap nearly constant. This work therefore first step towards pulsed laser-driven sources time-resolved radiation...
Efficient coupling of laser energy into hohlraum targets is important for indirect drive ignition. Laser-plasma instabilities can reduce coupling, symmetry, and cause preheat. We consider the effects an external magnetic field on laser-energy in targets. Experiments were performed at Omega Laser Facility using low-Z gas-filled which placed a coil with Bz ≤ 7.5-T. found that = 7.5-T aligned along axis results up to 50% increase plasma temperature as measured by Thomson scattering. The...
We have developed an experimental platform for the National Ignition Facility that uses spherically converging shock waves absolute equation-of-state (EOS) measurements along principal Hugoniot. In this Letter, we present one indirect-drive implosion experiment with a polystyrene sample employs radiographic compression over range of pressures reaching up to 60 Mbar (6 TPa). This significantly exceeds previously published results obtained on Nova laser [R. Cauble et al., Phys. Rev. Lett. 80,...
Warm dense matter plays an important role in astrophysical objects and technological applications, but the rigorous diagnostics of corresponding experiments is notoriously difficult. In this work, we present a model-free analysis x-ray Thomson scattering (XRTS) measurements on isochorically heated graphite obtained at Linac Coherent Light Source multiple angles. We demonstrate that recent imaginary-time thermometry technique works for data have been measured both forward backward geometry....
Short pulse laser (SPL) heated matter has opened an avenue to studying at conditions previously unattainable. While SPLs can generate extreme densities and temperatures, characterization of the be extremely challenging. The are dynamic require careful monitoring plasma evolution. Atomic processes under these provide a powerful tool study fundamental properties as they evolve. When utilizing x-ray emission from plasmas, it is often useful resolve spectral details with high resolution....
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...
Angularly resolved X-ray scattering measurements from fs-laser heated hydrogen have been used to determine the equilibration of electron and ion temperatures in warm dense matter regime. The relaxation rapidly cryogenic is visualized using 5.5 keV pulses Linac Coherent Light (LCLS) source a 1 Hz repetition rate pump-probe setting. We demonstrate that electron-ion energy transfer faster than quasi-classical Landau-Spitzer models use ad hoc cutoffs Coulomb logarithm.
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...
Studies were performed to obtain evidence for glyconeogenesis from pyruvate the triose phosphates in pancreatic islets. Inability show this would be consistent with fact that glyceraldehyde, but not pyruvate, is a potent insulin secretagogue. Synthesis of 14C-labelled glucose could detected. Since might have been due lack sensitivity required measure 14C-glucose production such scarce tissue as islets, cDNA probes used estimate relative expression genes coding gluconeogenic enzymes. Islets...