A5074731779- Laser-Plasma Interactions and Diagnostics
- Pulsed Power Technology Applications
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Magnetic confinement fusion research
- Gyrotron and Vacuum Electronics Research
- Laser-induced spectroscopy and plasma
- Electrostatic Discharge in Electronics
- Ion-surface interactions and analysis
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Dust and Plasma Wave Phenomena
- Superconducting Materials and Applications
- Laser-Matter Interactions and Applications
- Mass Spectrometry Techniques and Applications
- Plasma Applications and Diagnostics
- Radiation Effects and Dosimetry
- Laser Design and Applications
- High-pressure geophysics and materials
- GaN-based semiconductor devices and materials
- Vacuum and Plasma Arcs
Voss Scientific (United States)
2015-2024
Institute of Electrical and Electronics Engineers
2024
University of California, San Diego
2023
Manufacturing Advocacy & Growth Network (United States)
2023
Sandia National Laboratories California
2004-2022
Lawrence Livermore National Laboratory
1999-2019
University of Washington
2011-2019
Sandia National Laboratories
2003-2018
Princeton Plasma Physics Laboratory
2004-2018
Weizmann Institute of Science
2018
High current, energetic protons are produced by irradiating thin metal foils with intense lasers. Here, the laser plasma interaction produces relativistic electrons at critical surface. These propagate through foil and create a space-charge cloud that accelerates proton contaminants on back side. Self-consistent electromagnetic simulations of this process using hybrid particle-in-cell code show importance detailed modeling electron production transport, as well distributed acceleration...
Longitudinal compression of a velocity-tailored, intense neutralized ${\mathrm{K}}^{+}$ beam at 300 keV, 25 mA has been demonstrated. The takes place in 1--2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces head-to-tail velocity ramp that longitudinally compresses the beam, enhancing peak current by factor 50 and producing pulse duration about 3 ns. This measurement confirmed independently two different diagnostic systems.
Spherically imploding plasma liners formed by merging an array of high Mach number jets are a proposed standoff driver for magnetoinertial fusion (MIF). This paper gives updated concept-level overview liner MIF, including advanced notions such as methods forming and magnetizing the fuel target shaping to optimize dwell time. Results from related 1-D radiation-hydrodynamic simulations targetless implosions summarized along with new analysis on efficiency conversion initial kinetic energy...
The objectives of this tutorial are as follows: 1) to help students and researchers develop a basic understanding how pulsed-power systems used create high-energy-density (HED) matter; 2) new, compact, efficient technology called linear transformer drivers (LTDs); 3) understand why LTDs an attractive for driving HED physics (HEDP) experiments; 4) contrast with the more traditional Marx-generator/pulse-forming-line approach HEDP 5) briefly review history LTD well some LTD-driven research...
A three-dimensional, fully electromagnetic model of the principal pulsed-power components 26-MA ZR accelerator [D. H. McDaniel et al., in Proceedings 5th International Conference on Dense $Z$-Pinches (AIP, New York, 2002), p. 23] has been developed. This large-scale simulation tracks evolution waves through accelerator's intermediate-storage capacitors, laser-triggered gas switches, pulse-forming lines, water triplate transmission and convolute to vacuum insulator stack. The insulator-stack...
Dense plasma focus Z-pinch devices are sources of copious high energy electrons and ions, x rays, neutrons. The mechanisms through which these physically simple generate such high-energy beams in a relatively short distance not fully understood. We now have, for the first time, demonstrated capability to model plasmas kinetically, allowing us simulate pinch process at particle scale. present here results initial kinetic simulations, reproduce experimental neutron yields (~10(7)) (MeV) time....
The walls of the hohlraum used in experiments at national ignition facility are heated by laser beams with intensities ∼1015 W/cm2, a wavelength ∼1/3 μm, and pulse lengths on order ns, collisional absorption believed to be primary heating mechanism. X-rays generated hot ablated plasma gold then implode target interior. In addition energy walls, non-linear laser-plasma interactions (LPI), such as stimulated Raman scattering two plasmon decay, generate population supra-thermal electrons which,...
The electron-beam-driven self-magnetically pinched diode is a candidate for future flash X-ray radiographic sources. As presently fielded on Sandia Laboratories' six-cavity Radiographic Integrated Test Stand (RITS-6), the capable of producing sub 3-mm radiation spot sizes and greater than 350 rads hard X-rays at 1 m. operates between 6 7 MV with slowly decreasing impedance that falls from approximately 65 to 40 Ω during main pulse. Sensitivity in operation affected by interaction evolving...
Fully kinetic simulations have demonstrated that at sufficiently high currents, half of the neutrons produced by a deuterium Z-pinch are thermonuclear in origin. At 150-kA pinch current, O. A. Anderson et al. [Phys. Rev. 110, 1375 (1958)] clearly shows essentially all not thermonuclear, but initiated an instability creates beam-target neutrons. Since this paper, many subsequent authors supported result while others claimed are, on contrary, thermonuclear. To resolve issue, fully kinetic,...
It is shown by means of multi-fluid particle-in-cell simulations that convergence the spherical shock wave propagates through inner gas inertial confinement fusion-relevant experiments accompanied a separation deuterium (D) and tritium (T) ions across front. Deuterons run ahead tritons due to their lower mass higher charge-to-mass ratio can reach center several tens picoseconds before tritons. The rising edge DD TT fusion rate also temporally separated same amount, which should be an...
Uncontrolled plasma formation on electrode surfaces limits performance in a wide variety of pulsed power devices such as electron and ion diodes, transmission lines, radio frequency (RF) cavities, microwave devices. Surface bulk contaminants the electrodes vacuum dominate composition these plasmas, formed through processes stimulated thermal desorption followed by ionization. We are applying RF discharge cleaning, anode heating, cathode cooling, substrate surface coatings to control effects...
An updated, self-consistent point design for a heavy ion fusion (HIF) power plant based on an induction linac driver, indirect-drive targets, and thick liquid wall chamber has been completed. Conservative parameters were selected to allow each area meet its functional requirements in robust manner, thus this is referred as the Robust Point Design (RPD-2002). This paper provides top-level summary of major characteristics target, final focus magnet layout shielding, chamber, beam propagation...
Experimental techniques to provide active neutralization for space-charge-dominated beams as well prevent uncontrolled ion beam by stray electrons have been demonstrated. Neutralization is provided a localized plasma injected from cathode arc source. Unwanted secondary produced at the wall halo particle impact are suppressed using radial mesh liner that positively biased inside drift tube. Measurements of current transmission, spot size function axial position, energy, and source conditions...
AbstractThe long-range goal of the Z-Pinch IFE program is to produce an economically-attractive power plant using high-yield z-pinch-driven targets (~3GJ) with low rep-rate per chamber (~0.1 Hz). The present mainline choice for a uses LTD (Linear Transformer Driver) repetitive pulsed driver, Recyclable Transmission Line (RTL), dynamic hohlraum target, and thick-liquid wall chamber. RTL connects driver directly made from frozen coolant or material that easily separable (such as carbon steel)....
We report on unique particle-in-cell simulations to understand the relativistic electron beam thermalization and subsequent heating of highly compressed plasmas. The yield heated core parameters in good agreement with GEKKO-PW experimental measurements, given reasonable assumptions laser-to-electron coupling efficiency distribution function laser-produced electrons. classical range hot electrons exceeds mass density-core diameter product rhoL by a factor several. Anomalous stopping appears...
Vacuum-post-hole convolutes are used in pulsed high-power generators to join several magnetically insulated transmission lines (MITL) parallel. Such add the output currents of MITLs, and deliver combined current a single MITL that, turn, delivers load. Magnetic insulation electron flow, established upstream convolute region, is lost at due symmetry breaking formation magnetic nulls, resulting some losses. At very operating levels long pulse durations, expansion electrode plasmas into such...
New numerical techniques for simulating the formation and evolution of cathode anode plasmas have been successfully implemented in a hybrid code. The dynamics expanding electrode has long recognized as limiting factor impedance lifetimes high-power vacuum diodes magnetically insulated transmission lines. Realistic modeling such is being pursued to aid understanding operating characteristics these devices well establishing scaling relations reliable extrapolation higher voltages. Here,...
A challenge for the TW-class accelerators driving $Z$-pinch experiments, such as Sandia National Laboratories' $Z$ machine, is to efficiently couple power from multiple storage banks into a single multi-MA transmission line. The physical processes that lead current loss are identified in new large-scale, multidimensional simulations of machine. Kinetic models follow range physics occurring during pulse, vacuum pulse propagation charged-particle emission and magnetically-insulated flow...
Recent studies of power flow and particle transport in multi-MA pulsed-power accelerators demonstrate that electrode plasmas may reduce accelerator efficiency by shunting current upstream from the load [Bennett et al., Phys. Rev. Accel. Beams 24, 060401 (2021)]. The detailed generation evolution these are examined here using fully relativistic, Monte Carlo particle-in-cell (PIC) magnetohydrodynamic (MHD) simulations over a range peak currents (8--48 MA). PIC calculations, informed vacuum...