Roger Alan Vesey

ORCID: 0009-0005-2341-6847
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About
Contact & Profiles
Research Areas
  • Laser-Plasma Interactions and Diagnostics
  • Magnetic confinement fusion research
  • Laser-Matter Interactions and Applications
  • Pulsed Power Technology Applications
  • Fusion materials and technologies
  • High-pressure geophysics and materials
  • Laser-induced spectroscopy and plasma
  • Particle accelerators and beam dynamics
  • Laser Design and Applications
  • Nuclear Physics and Applications
  • Plasma Diagnostics and Applications
  • Cold Fusion and Nuclear Reactions
  • Atomic and Molecular Physics
  • Particle Accelerators and Free-Electron Lasers
  • Electrostatic Discharge in Electronics
  • Superconducting Materials and Applications
  • Combustion and Detonation Processes
  • Ion-surface interactions and analysis
  • Energetic Materials and Combustion
  • Electromagnetic Launch and Propulsion Technology
  • Gyrotron and Vacuum Electronics Research
  • Radiation Effects in Electronics
  • Fusion and Plasma Physics Studies
  • X-ray Spectroscopy and Fluorescence Analysis
  • Silicon Carbide Semiconductor Technologies

Sandia National Laboratories
2011-2025

University of California, San Diego
2023

Manufacturing Advocacy & Growth Network (United States)
2023

United States Naval Research Laboratory
2022

Sandia National Laboratories California
2005-2013

National Technical Information Service
2003-2008

Office of Scientific and Technical Information
2003-2008

Laboratoire de Physique des Plasmas
2008

University of Nevada, Reno
2008

École Polytechnique
2008

The radial convergence required to reach fusion conditions is considerably higher for cylindrical than spherical implosions since the volume proportional r2 versus r3, respectively. Fuel magnetization and preheat significantly lowers enabling become an attractive path toward generating conditions. Numerical simulations are presented indicating that significant yields may be obtained by pulsed-power-driven of metal liners onto magnetized (>10 T) preheated (100–500 eV) deuterium-tritium...

10.1063/1.3333505 article EN Physics of Plasmas 2010-03-12

Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant yields, but it has been widely accepted that gain is not sufficient energy. Numerical simulations are presented showing high-gain MIF possible in cylindrical liner implosions based on MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)] with addition a cryogenic layer deuterium-tritium (DT). These show burn wave propagates radially from magnetized hot...

10.1103/physrevlett.108.025003 article EN publisher-specific-oa Physical Review Letters 2012-01-12

The Z accelerator [R. B. Spielman, W. A. Stygar, J. F. Seamen et al., Proceedings of the 11th International Pulsed Power Conference, Baltimore, MD, 1997, edited by G. Cooperstein and I. Vitkovitsky (IEEE, Piscataway, NJ, 1997), Vol. 1, p. 709] at Sandia National Laboratories delivers ∼20MA load currents to create high magnetic fields (>1000T) pressures (megabar gigabar). In a z-pinch configuration, pressure (the Lorentz force) supersonically implodes plasma created from cylindrical...

10.1063/1.1891746 article EN Physics of Plasmas 2005-05-01

The magnetized liner inertial fusion concept has been presented as a path toward obtaining substantial thermonuclear yields using the Z accelerator [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)]. We present first integrated magnetohydrodynamic simulations of targets, which self-consistently include laser preheating fuel, presence electrodes, and end loss effects. These numerical provided design for neutron-producing experiments on capabilities that presently exist: peak currents Imax...

10.1063/1.4890298 article EN cc-by Physics of Plasmas 2014-07-01

We have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and 800. The are based on an accelerator architecture that is founded concepts: single-stage electrical-pulse compression impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. prime power source each machine consists 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, which powered by 5-GW bricks parallel. (A brick a single...

10.1103/physrevstab.18.110401 article EN cc-by Physical Review Special Topics - Accelerators and Beams 2015-11-30

Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing physics of burn product confinement. Diagnosing level magnetization during is critical to understanding target performance magneto-inertial (MIF) implosions. In pure deuterium plasma, 1.01 MeV tritons are emitted deuterium-deuterium can undergo secondary deuterium-tritium reactions before exiting fuel. Increasing elongates path lengths through some tritons,...

10.1103/physrevlett.113.155004 article EN publisher-specific-oa Physical Review Letters 2014-10-06

The implosions of initially solid beryllium liners (tubes) have been imaged with penetrating radiography through to stagnation. These novel radiographic data reveal a high degree azimuthal correlation in the evolving magneto-Rayleigh-Taylor structure at times just prior (and during) stagnation, providing stringent constraints on simulation tools used by broader energy density physics and inertial confinement fusion communities. To emphasize this point, comparisons 2D 3D radiation...

10.1103/physrevlett.109.135004 article EN publisher-specific-oa Physical Review Letters 2012-09-28

Enhanced implosion stability has been experimentally demonstrated for magnetically accelerated liners that are coated with 70 μm of dielectric. The dielectric tamps liner-mass redistribution from electrothermal instabilities and also buffers coupling the drive magnetic field to magneto-Rayleigh-Taylor instability. A dielectric-coated axially premagnetized beryllium liner was radiographed at a convergence ratio [CR=Rin,0/Rin(z,t)] 20, which is highest CR ever directly observed strengthless...

10.1103/physrevlett.116.065001 article EN publisher-specific-oa Physical Review Letters 2016-02-10

The magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of confinement fusion. first experiments test [M. R. Gomez Rev. Lett. 113, 155003 (2014)] were conducted utilizing 19 MA, 100 ns Z machine, 2.5 kJ, 1 TW Beamlet laser, 10 T Applied B-field on system. Despite an estimated implosion velocity only 70 km/s in these experiments, electron ion temperatures at stagnation as...

10.1063/1.4919394 article EN Physics of Plasmas 2015-04-29

We have measured the x-ray power and energy radiated by a tungsten-wire-array z pinch as function of peak current width anode-cathode gap at base pinch. The measurements were performed 13- 19-MA currents 1-, 2-, 3-, 4-mm gaps. wire material, number wires, wire-array diameter, length, wire-array-electrode design, normalized-pinch-current time history, implosion time, diagnostic package held constant for experiments. To keep constant, mass array was increased I2 (i.e., diameter each I), where...

10.1103/physreve.69.046403 article EN Physical Review E 2004-04-14

Hohlraums measuring 6 mm in diameter by 7 height have been heated x rays from a $Z$ pinch. Over the measured x-ray input powers $P$ of 0.7 to 13 TW, hohlraum radiation temperature $T$ increases $\ensuremath{\sim}55$ $\ensuremath{\sim}130\mathrm{eV}$, and is agreement with Planckian relation $T\ensuremath{\sim}{P}^{1/4}$. The results suggest that indirect-drive inertial-confinement-fusion experiments involving National Ignition Facility relevant pulse shapes $<2\mathrm{mm}$ capsules can be...

10.1103/physrevlett.83.5511 article EN Physical Review Letters 1999-12-27

Over the last several years, rapid progress has been made evaluating double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough drive high yield ICF capsule. The irradiated sides by z-pinches produce low odd-mode asymmetry. This double-pinch source driven single electrical power...

10.1088/0741-3335/48/2/r01 article EN Plasma Physics and Controlled Fusion 2006-01-13

The radiation and shock generated by impact of an annular tungsten $Z$-pinch plasma on a 10-mm diam $5\mathrm{\text{\ensuremath{-}}}\mathrm{m}\mathrm{g}/\mathrm{c}\mathrm{c}$ $\mathrm{C}{\mathrm{H}}_{\mathrm{2}}$ foam are diagnosed with x-ray imaging power measurements. radiative was virtually unaffected instabilities. 5-ns-duration $\ensuremath{\sim}135\mathrm{\text{\ensuremath{-}}}\mathrm{e}\mathrm{V}$ field imploded 2.1-mm-diam CH capsule. measured temperature, radius, capsule radius...

10.1103/physrevlett.89.095004 article EN Physical Review Letters 2002-08-13

A key demonstration on the path to inertial fusion energy is achievement of high yield (hundreds MJ) and target gain. Toward this goal, an indirect-drive high-yield confinement (ICF) involving two Z-pinch x-ray sources heating a central secondary hohlraum described by Hammer et al. [Phys. Plasmas 6, 2129 (1999)]. In subsequent research at Sandia National Laboratories, theoretical/computational models have been developed extensive series validation experiments performed study energetics,...

10.1063/1.2472364 article EN Physics of Plasmas 2007-03-22

Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (∼1012 DD neutrons) from multi-keV deuterium plasmas inertially confined by slow (∼10 cm/μs), stable, cylindrical implosions. Effective magnetic confinement of charged reactants and products is signaled high secondary DT above 1010. Analysis extensive power, imaging, spectroscopic x-ray measurements provides a detailed picture ∼3 keV temperatures,...

10.1063/1.4921217 article EN publisher-specific-oa Physics of Plasmas 2015-05-01

The Magnetized Liner Inertial Fusion concept (MagLIF) [Slutz et al., Phys. Plasmas 17, 056303 (2010)] is being studied on the Z facility at Sandia National Laboratories. Neutron yields greater than 1012 have been achieved with a drive current in range of 17–18 MA and pure deuterium fuel [Gomez Rev. Lett. 113, 155003 (2014)]. We show that 2D simulated are about twice best obtained likely cause this difference mix material into fuel. Mitigation strategies presented. Previous numerical studies...

10.1063/1.5054317 article EN Physics of Plasmas 2018-11-01

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...

10.1109/27.602495 article EN IEEE Transactions on Plasma Science 1997-04-01

An indirect drive configuration is proposed wherein multiple compact Z-pinch x-ray sources surround a secondary hohlraum. Planar wire arrays allow reduced primary hohlraum surface area compared to cylindrical loads. Implosions of planar are studied at up 15 TW power on Saturn with radiated yields exceeding the calculated kinetic energy, suggesting other heating paths. X-ray and yield scaling from 1-6 MA motivates viewfactor modeling four 6-MA producing 90 eV radiation temperature in

10.1103/physrevlett.104.125001 article EN Physical Review Letters 2010-03-22

The size, temporal and spatial shape, energy content of a laser pulse for the pre-heat phase magneto-inertial fusion affect ability to penetrate window laser-entrance-hole heat fuel behind it. High intensities dense targets are subject laser-plasma-instabilities (LPI), which can lead an effective loss or pronounced heating areas that should stay unexposed. While this problem has been many studies over last decades, investigated parameters were typically geared towards traditional driven...

10.1063/1.5003038 article EN publisher-specific-oa Physics of Plasmas 2018-02-01

Implosions of magnetically driven annular shells (Z pinches) are studied in the laboratory to produce high-energy-density plasmas. Such plasmas have a wide-range applications including x-ray generation, controlled thermonuclear fusion, and astrophysics studies. In this work, we theoretically investigate in-flight dynamics driven, imploding cylindrical shell that stagnates onto itself upon collision on axis. The converging flow Z-pinch is analyzed by considering implosion trajectory (A, M)...

10.1063/5.0242367 article EN cc-by-nc-nd Physics of Plasmas 2025-01-01

Implosions of magnetically-driven annular shells (Z pinches) are studied in the laboratory to produce high-energy-density plasmas. Such plasmas have a wide-range applications including x-ray generation, controlled thermonuclear fusion, and astrophysics studies. In this work, we theoretically investigate in-flight dynamics magnetically-driven, imploding cylindrical shell that stagnates onto itself upon collision on axis. The converging flow Z-pinch is analyzed by considering implosion...

10.48550/arxiv.2501.12284 preprint EN arXiv (Cornell University) 2025-01-21

Simulations have been useful for improving the design of dynamic hohlraums purpose imploding inertial fusion capsules [S. A. Slutz, J. E. Bailey, G. Chandler et al., Phys. Plasmas 10, 1875 (2003)]. These changes, which resulted in capsule implosions with hot dense cores [J. Chandler, S. Slutz Rev. Lett. 92, 085002 (2004)] and production thermonuclear neutrons [C. L. Ruiz, Cooper, 93, 015001 (2005)], were based primarily on a series one-dimensional numerical simulations, treated hohlraum...

10.1063/1.2354587 article EN Physics of Plasmas 2006-10-01

Experimental data is presented that illustrates important displacement current phenomena in the magnetically insulated transmission lines (MITLs) of refurbished $Z$ accelerator [D. V. Rose et al., Phys. Rev. ST Accel. Beams 13, 010402 (2010)]. Specifically, we show how MITLs causes significant differences between measured at vacuum-insulator stack (at a radial position about 1.6 m from axis symmetry) and load 6 cm symmetry). The importance accounting for these was first emphasized by...

10.1103/physrevstab.13.120401 article EN cc-by Physical Review Special Topics - Accelerators and Beams 2010-12-27

A quasianalytic model of the dynamic hohlraum is presented. Results are compared to both experiments and full numerical simulations with good agreement. The computational simplicity allows one find behavior radiation temperature as a function various parameters system thus optimum driving current. used investigate benefits ablative standoff quasispherical Z pinches.

10.1063/1.1360213 article EN Physics of Plasmas 2001-05-01

Simulations of a double Z-pinch hohlraum, relevant to the high-yield inertial-confinement-fusion concept, predict that through geometry design time-integrated P2 Legendre mode drive asymmetry can be systematically controlled from positive negative coefficient values. Studying capsule elongation, recent experiments on Z confirm such control by varying secondary hohlraum length. Since experimental trend and optimum length are correctly modeled, confidence is gained in simulation tools; same...

10.1103/physrevlett.90.035005 article EN Physical Review Letters 2003-01-23
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