A5035903780- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Laser-induced spectroscopy and plasma
- Electromagnetic Launch and Propulsion Technology
- Gyrotron and Vacuum Electronics Research
- Vacuum and Plasma Arcs
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Quantum, superfluid, helium dynamics
- Metal and Thin Film Mechanics
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Diamond and Carbon-based Materials Research
- Atomic and Molecular Physics
- Quantum chaos and dynamical systems
- Cold Fusion and Nuclear Reactions
- Plasma Applications and Diagnostics
- Laser Design and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Laser-Matter Interactions and Applications
- Geophysics and Sensor Technology
- Experimental and Theoretical Physics Studies
United States Naval Research Laboratory
1992-2024
Commonwealth Computer Research (United States)
2010
Naval Research Laboratory Plasma Physics Division
1985-2007
Edinburgh Napier University
2007
RTI International
1999
University of Maryland, College Park
1978
The University of Texas at Austin
1972
Culham Science Centre
1965-1967
United Kingdom Atomic Energy Authority
1959-1965
Atomic Energy (Canada)
1959-1961
We have formed dense Z pinches from frozen deuterium fibers ranging in diameter 80 to 125 \ensuremath{\mu}m and at peak currents of up 640 kA. The pinch remains stable for the entire 130 nsec current rise. This anomalously long period corresponds about 100 MHD growth times. As soon as peaks, i.e., when dI/dt=0, goes rapidly m=0 unstable produces nearly ${10}^{12}$ neutrons a 30--60-nsec-wide pulse. instability occurs only dI/dt=0 is independent either magnitude or time peak.
Experiments are described in which the application of a pulsed magnetic field to Corbino disk indium antimonide causes an increase resistance about 2 orders magnitude time 5 μsec. The use this element as switch for transfer energy from inductive store is discussed.
It is shown theoretically that a cathode spot may be maintained on an isolated metal surface immersed in the plasma of gas discharge. Two experiments are described which arcs this kind were produced mercury surface.
Most metals when used as the cathode of an arc discharge cannot reach temperatures sufficiently high to emit electrons thermionically. However, are enough produce considerable evaporation. Mercury and copper examples. The older theories suggest that here current at is carried by extracted field emission, photo-electric emission or secondary positive ions, entire ions produced thermal ionization in gas. All shown be quantitatively inconsistent with observations. A new theory suggested:...
A special probe has been used to detect ions reflected from a collisionless shock wave propagating perpendicular the field in magnetized, low-$\ensuremath{\beta}$ plasma. Reflected are observed only above critical Alfv\'en number ${M}_{A}\ensuremath{\approx}2.7$, and their orbits coincide with familiar "foot" on magnetic structure of supercritical shocks. We discuss origin ions.
We are carrying out a multidisciplinary multi-institutional program to develop the scientific and technical basis for inertial fusion energy (IFE) based on laser drivers direct-drive targets. The key components developed as an integrated system, linking science, technology, final application of 1000-MWe pure-fusion power plant. science technologies here flexible enough be applied other size systems. justification this work is family target designs (simulations) that show direct drive has...
When an electric arc with evaporating cathode (e.g., copper) is exposed to a strong transverse magnetic field in atmospheric air, its motion can be made change from the conventional reverse direction by reducing sufficiently electrode separation.The effect discussed terms of earlier idea based on resultant acting region. This composed applied and "loop" curved current path above spot. At low pressure, increase former accompanied rapid latter thus changes sign. Here at high pressure constant...
Received 29 December 1953DOI:https://doi.org/10.1103/PhysRev.93.1121.2©1954 American Physical Society
A low-pressure arc between copper electrodes has been driven by a transverse magnetic field of up to 5T. At low the moves in retrograde direction, but above about 1T motion changes amperian direction. This result is consistent with theory proposed Robson and von Engel (1954).
A plane sheet of partially ionized plasma produced by a pulsed, hollow-cathode glow discharge in an axial magnetic field has been shown to reflect X-band microwaves as well equivalent metal. The mirror can be established and extinguished on time scale about 20 mu s could form the basis extremely agile radar system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
The Naval Research Laboratory (NRL) has been studying the use of a magnetically confined plasma sheet as reflector for high-frequency (X-band) microwaves broadband radar applications [IEEE Trans. Plasma Sci. PS-19, 1228 (1991)]. A planar (50 cm×60 cm×1 cm) is produced using 2–10 kV fast rise time square wave voltage source and linear hollow cathode. Reproducible distributions with density ≥1.2×1012 cm−3 have formed in low-pressure (100–500 mTorr air) chamber located inside 100–300 G uniform...
A reversed-field plasma confinement geometry has been produced by currents induced a rotating relativistic electron beam injected into 85 mTorr neutral hydrogen. The resulting belt-pinch-like configuration rectangular cross section, with length-to-width ratio of 20, and midplane β=0.5. An equilibrium model, fitted to measurements the excluded flux axial (ΔBz) azimuthal (Bϑ) magnetic fields, is in agreement annular observed radial Thomson scattering scans, CO2 interferometry, end-on streak...
A novel method of injection into a mirror machine, reported recently by Sinelnikov et al., is analysed in detail numerical and perturbation solutions the equations motion single particle. The principle to inject particles through one mirrors, along lines force. magnetic field centre machine has small, spatially periodic radial component which, for certain initial conditions, causes resonant interchange energy from longitudinal transverse particle's velocity. This results reflection end...
The radiative collapse of a Z pinch in hydrogen or helium is examined from practical viewpoint. maximum density that may be achieved calculated by modifying the Pease–Braginskii current to include effect opacity and incorporating into realistic circuit. It found increased addition series inductance inside vacuum chamber. In most cases limit determined becoming optically thick, although for low line large set onset electron degeneracy. Pinches lead denser collapsed states than pinches helium.
A rotating relativistic electron beam, charge but not current neutralized and exceeding the Alfv\'en limit, has been propagated down a closed metal tube in absence of an external guide field. The radial equilibrium is determined by self-fields beam induced wall currents. 100-nsec duration upon leaving system, induces plasma currents that maintain field-reversed configuration for 18 \ensuremath{\mu}sec.
The evolution of a linear z-pinch in which the current rises at constant rate is analysed terms quasi-static pinch model. It shown that there maximum hydrogen or deuterium equal to approximately 31/2 times Pease-Braginskij cannot be exceeded because radiative collapse. Higher currents may obtained D-T heating by alpha particles prevents collapse until most fusion fuel consumed, point collapses like star. implications for as system are discussed and it that, if remains stable while rising,...
The penetration of a magnetic pulse into cylindrical, field-free plasma has been studied under conditions where the was determined by turbulent conductivity. time found to vary as $\frac{{({M}_{i}{n}_{e})}^{\frac{1}{2}}}{B}$, ${M}_{i}$ is ion mass, ${n}_{e}$ electron density, and ${B}_{0}$ peak amplitude applied field. This corresponds mean conductivity $\ensuremath{\sigma}\ensuremath{\propto}\frac{{M}_{i}{n}_{e}}{B_{0}^{}{}_{}{}^{2}}$. These results can not be accounted for any present...
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A two-dimensional resistive magnetohydrodynamic (MHD) code is used to examine the stability of a Z pinch m=0 perturbations under conditions rising current. The current waveform chosen keep unperturbed radius constant in time. At low oscillate without growing, or grow only weakly, contrary predictions ideal MHD theory. high current, at rate consistent with MHD. point transition can be described terms critical Lundquist number; this increases wavelength perturbation, and about 160 for ka=0.3,...
The characteristic whistler structure of oblique hydromagnetic shocks is observed experimentally to suffer from a rapidly growing short-wavelength instability, which tentatively identified as the decay instability first predicted by Galeev and Karpman. It suggested that this responsible for turbulent shock when super-Alfv\'enic plasma stream encounters magnetic obstacle.