A5044364149- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Laser-induced spectroscopy and plasma
- Dust and Plasma Wave Phenomena
- Solar and Space Plasma Dynamics
- Gyrotron and Vacuum Electronics Research
- Pulsed Power Technology Applications
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Fusion materials and technologies
- Gas Dynamics and Kinetic Theory
- Plasma Applications and Diagnostics
- Ion-surface interactions and analysis
- Geomagnetism and Paleomagnetism Studies
- Electron and X-Ray Spectroscopy Techniques
- Laser Design and Applications
- Advanced Thermodynamics and Statistical Mechanics
- Plasma and Flow Control in Aerodynamics
- Laser-Matter Interactions and Applications
- Electromagnetic Launch and Propulsion Technology
- Astro and Planetary Science
- Photocathodes and Microchannel Plates
Lawrence Livermore National Laboratory
2017-2025
Princeton University
2020
University of California, San Diego
2009-2018
United States Naval Research Laboratory
2013-2016
Naval Research Laboratory Plasma Physics Division
2015
The application of an external 26 Tesla axial magnetic field to a D2 gas-filled capsule indirectly driven on the National Ignition Facility is observed increase ion temperature by 40% and neutron yield factor 3.2 in hot spot with areal density approaching what required for fusion ignition [1]. improvements are determined from energy spectral measurements 2.45 MeV neutrons D(d,n)3He reaction, compressed central core B estimated be ∼4.9 kT using 14.1 secondary D(T,n)4He reactions. experiments...
Most of the work to date on plasma blobs found in edge region magnetic confinement devices is limited 2D theory and simulations which ignore variation blob parameters along field line. However, if convective rate order growth unstable drift waves, then wave turbulence can drastically alter dynamics from that predicted by theory. The density gradients plane characterize are mostly depleted during nonlinear stage waves resulting a much more diffuse with greatly reduced radial velocity. Sheath...
The 3D effects on sheath connected plasma blobs that result from parallel electron dynamics are studied by allowing for the variation of blob density and potential along magnetic field line using collisional Ohm’s law to model current density. linear theory, typically used in 2D model, is implemented as boundary conditions. This includes electrostatic effects, such resistive drift waves spinning, while retaining all fundamental physics blobs. If growth time unstable comparable advection...
The particle-in-cell (PIC) and Monte Carlo collisions (MCC) methods are workhorses of many numerical simulations physical systems. Recently, it was pointed out that, while the two can be exactly—or nearly—energy-conserving independently, combining leads to anomalous heating. This paper reviews standard explicit PIC-MCC algorithm, elucidates origins heating, explains how couple such that heating is avoided. Published by American Physical Society 2025
Coulomb collision is a fundamental diffusion process in plasmas that can be described by the Landau-Fokker-Planck (LFP) equation or stochastic differential (SDE). While energy and momentum are conserved exactly LFP equation, they only on average conventional corresponding SDEs, suggesting underlying may not well defined such SDEs. In this study, we derive new SDEs with exact energy-momentum conservation for factorizing collective effect of field particles into individual enforcing Newton's...
Dense plasma focii (DPFs) are appealing as energy efficient sources of short pulses ions, neutrons, and x rays. The output these is expected to scale with input current (I4), but has been shown drop at the MA level [S. K. H. Auluck, “On failure neutron yield scaling in dense focus,” Phys. Plasmas 30, 080701 (2023)]. New results on MegaJOuLe Neutron Imaging Radiography DPF showed production agreement beyond previously observed drop. This work provides insight into pinch formation a reports...
Fluctuations in fusion boundary and similar plasmas often have the form of filamentary structures, or blobs, that convectively propagate radially. This may lead to degradation plasma facing components as well confinement. Theoretical analysis blobs usually takes advantage so-called Boussinesq approximation potential vorticity equation, which greatly simplifies treatment analytically numerically. is only strictly justified when blob density amplitude small with respect background plasma....
Abstract In situ monitoring is required to improve the understanding and increase reliability of additive manufacturing methods such as laser powder bed fusion (LPBF). Current diagnostic for LPBF capture optical images, X-ray radiographs, or measure emission thermal acoustic signals from component. Herein, a methodology based on electrons - thermionic metal surface during proposed which can resolve laser-material interaction dynamics. The high sensitivity temperature morphology revealed...
Magnetizing a cryogenic deuterium–tritium (DT)-layered inertial confinement fusion (ICF) implosion can improve performance by reducing thermal conduction and improving DT-alpha in the hot spot. A room-temperature, magnetized indirect-drive ICF platform at National Ignition Facility has been developed, using high-Z, high-resistivity AuTa4 alloy as hohlraum wall material. Experiments show 2.5× increase deuterium–deuterium (DD) neutron yield 0.8-keV hot-spot temperature with application of 12-T...
The dynamical formation of a Z-pinch in the strong-shock limit is studied this paper using one-dimensional (1D) simulations two-temperature magnetohydrodynamic model. classic 1D picture consists three stages: run-in, reflected-shock, and expansion. special case constant current I uniform gas fill, which are approximate conditions pinch-formation stage dense plasma focus, examined detail. Time-profiles for shock-front piston positions during run-in compared with some commonly used 0D models...
The impacts of the electromagnetic effects on blob dynamics are considered. Electromagnetic BOUT++ simulations seeded high-beta blobs demonstrate that inhomogeneity magnetic curvature or plasma pressure along filament leads to bending filaments and field lines due increased propagation time current (Alfvén time). motion can enhance heat exchange between facing materials inner scrape-off layer (SOL) region. sheath boundary conditions part away from also diminished by Alfvén time. Using linear...
A dense plasma focus (DPF) is a relatively compact coaxial gun, which completes its discharge as Z-pinch. These devices are designed to operate at variety of scales produce short (<100 ns) pulses ions, X-rays, and/or neutrons. LLNL recently constructed and brought into operation new device, the MegaJOuLe Neutron Imaging Radiography (MJOLNIR) DPF, for radiography high-yield operations. This device has been commissioned achieved neutron yields up 3.8E11 neutrons/pulse 2.5-MA peak current while...
Abstract COGENT is a continuum gyrokinetic code for edge plasmas being developed by the Edge Simulation Laboratory collaboration. The distinguished application of fourth order conservative discretization, and mapped multiblock grid technology to handle geometric complexity tokamak edge. It written in v ‖ ‐ μ (parallel velocity – magnetic moment) coordinates, making use Poisson equation calculation self‐consistent electric potential. In present manuscript we report on implementation initial...
The standard local linear analysis of drift waves in a plasma slab is generalized to be valid for arbitrarily collisional electrons by considering the governed drift-kinetic equation with BGK-like (Bhatnagar-Gross-Krook) collision operator. obtained dispersion relation reduces that found from collisionless kinetic theory when frequency zero. Electron temperature fluctuations must retained fluid order obtain good quantitative agreement our general solution highly limit. Any discrepancies...
The pinch-formation stage of a deuterium dense plasma focus, and associated “shock-flash” neutron yield, is studied using 1D kinetic simulations considering column with initial pressure P, radius R, the compression to be driven by constant current I. relative behavior shown similar for fixed ratios characteristic ion mean free path at stagnation, λst/Rst. This dimensionless parameter scale like I4/(P3R5). ratio, R/Rst, found minimum when λst/Rst≈1 largest in collisionless limit where...
The effects of electromagnetic plane waves obliquely incident on a warm bounded plasma slab finite length L are studied by solving the coupled Vlasov–Maxwell set equations. It is shown that solution can be greatly simplified in limit where thermal most important expanding small parameters and introducing self-similar variables. These solutions reveal coupling with angle incidence negligible region bounce resonance anomalous skin effect. In effect, heating to scale linearly depth δa when...