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  • 1
    Electronic Resource
    Electronic Resource
    High-brightness electron-beam generation and transport (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2562-2571 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental results for a high-brightness electron-beam source are compared to results of numerical and analytic calculations. The 4-MV, 5-kA beam is generated from a velvet cathode and focused by a solenoidal magnet. Data for the diode impedance and the beam focusing length and spot size agree well with numerical simulations. The minimum spot size is consistent with a normalized Lapostolle emittance of 0.12 cm rad, yielding a brightness of 3.5×108 A/m2 rad2 . Transverse beam oscillations are observed in streak photographs and are thought to be caused by electromagnetic dipole modes in the diode cavity. The oscillation amplitude is significantly reduced by making the current rise more slowly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346480
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  • 2
    Electronic Resource
    Electronic Resource
    Filamentation instability of a self-pinched hollow electron beam (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 3074-3083 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Filamentation stability properties of a self-pinched hollow electron beam propagating through a collisional plasma channel are investigated within the framework of linearized Vlasov–Maxwell equations, assuming that the beam is thin and that the equilibrium and perturbed space-charge fields are neutralized by background plasma. It is further assumed that the perturbations are well tuned with kβbc+lωb and satisfy la(very-much-less-than)R0, where l and k are the azimuthal and axial wavenumbers, βbc and ωb are the axial velocity and the rotational frequency of the beam, and 2a and R0 are the thickness and mean radius of the beam. From the stability analysis, two distinctive unstable mechanisms are identified: the return-current driven instability and the resistively driven instability. It is also found that high-l-mode perturbations are easily stabilized by a spread in the canonical angular momentum. Making use of a linearized particle-in-cell code, numerical simulations are performed. The agreement between the analytical results and those of simulations is excellent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865468
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  • 3
    Electronic Resource
    Electronic Resource
    Electromagnetic instability in a quadrupole-focusing accelerator (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 1698-1703 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The addition of helical quadrupole focusing to a modified betatron configuration is shown to give rise to an electromagnetic instability under certain conditions. The instability arises from a three-wave coupling between the helical field, a transverse mode on the beam, and a transverse-electric waveguide mode. An analytic dispersion relation is derived. Several features of the instability are confirmed using three-dimensional computer simulations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865635
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  • 4
    Electronic Resource
    Electronic Resource
    Diffuse plasma effects on the ion-hose instability (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 339-343 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The transverse stability of a relativistic electron beam focused by an ion channel in the presence of a diffuse background plasma is investigated. The linear behavior of the ion-hose and electron two-stream instabilities is treated analytically using a spread-mass model for the beam and ion channel and a cold-fluid model for the plasma. The electron two-stream instability is found to be quite weak. As the plasma neutralization radius approaches the beam radius, the ion-hose growth rate is reduced up to 50% before the model's assumptions break down. Particle-in-cell simulations confirm the linear analytic theory and show that the electron two-stream instability can saturate nonlinearly with little beam emittance growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860518
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  • 5
    Electronic Resource
    Electronic Resource
    Calibration of the Joint European Torus energetic ion and alpha particle collective Thomson scattering diagnostic receiver : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1167-1170 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The receiver of the Joint European Torus (JET) energetic ion and alpha particle collective Thomson scattering diagnostic is calibrated assuming blackbody emission from the torus vacuum vessel (VV) and using electron cyclotron emission (ECE). The 32 receiver channels are absolutely calibrated with a mechanical chopper in the quasioptical arm of the receiver, alternating the receiver view between the torus vacuum at 320 °C and room temperature. This calibration is noisy due to the small difference between torus and room temperatures. A more accurate relative calibration is achieved with the ECE during plasma shots. The intensity of the ECE is found to be a smooth function of frequency, which enables the combination of the ECE calibration with the VV calibration. The accuracy of the absolute VV calibration is hereby improved to nearly the same standard as the relative ECE calibration. ECE signals measured by the calibrated receiver agree well with standard JET ECE diagnostics. Based on mathematical considerations presented here, noise is injected into the receiver final intermediate frequency stage during VV calibrations to provide more bit transitions for accurate analog-to-digital (AD) conversion of the low level calibration signals. This yields a resolution which is better than 1% of an (AD) step. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149475
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  • 6
    Electronic Resource
    Electronic Resource
    Resistive filamentation of self-pinched electron beams (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 577-584 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A model for resistive filamentation of a self-pinched slab electron beam is presented. The lowest-order modes are found to consist of a body mode which leads to bunching of the beam, and a surface mode which leads to rigid rippling of the beam. The dispersion relations for these modes are compared to results from a linearized particle simulation code. The analytic model and simulation code are applied to the interpretation of a recent experiment in which filamentation was observed in a self-pinched annular electron beam propagating in low-pressure air.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337450
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  • 7
    Electronic Resource
    Electronic Resource
    Einstein, Inventors, and Invention (1993)
    Cambridge : Cambridge University Press
    Science in context 6 (1993), S. 25-42 
    Details
    ISSN: 0269-8897
    Source: Cambridge Journals Digital Archives
    Topics: History , Natural Sciences in General
    Notes: The ArgumentAlbert Einstein had more than a passing and trivial involvement with patents and inventions. The historian seeking to fathom Einstein's thought processes would be ill-advised to pass lightly over his years at the Swiss Federal Patent office (1902–1909) and to consider his professional advice-giving about patents and his patenting of his inventions as merely peripheral to his core concerns and cognitive style. Years of reading patents and visualizing the machines, devices, and electromagnetic phenomena described in them is a formative experience. A number of inventors besides Einstein enhanced their power of visualization from reading and writing patent claims. It is reasonable to conclude that the Patent Office years honed his remarkable gift for visually conceptualizing systematic artifactual relationships that he used in articulating theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0269889700001290
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  • 8
    Electronic Resource
    Electronic Resource
    Model Builders and Instrument Makers (1988)
    Cambridge : Cambridge University Press
    Science in context 2 (1988), S. 59-75 
    Details
    ISSN: 0269-8897
    Source: Cambridge Journals Digital Archives
    Topics: History , Natural Sciences in General
    Notes: The ArgumentMany inventors, engineers, and scientists think in verbal images. Elmer Sperry (1860–1930), a noted American inventor, was able to “operate” in his mind's eye the machines he was developing. For inventors, engineers, and experimental scientists, visualization is often followed by construction of a physical model of the invention, which can be an experimental apparatus. The model, or apparatus, is then tested in increasingly complex environments and changes are made in the physical artifact until it is ready to be used. Examples of this process of development are Sperry's development of a ship stabilizer for the U.S. Navy and a revolving mirror to be used by Albert Michelson in the determination of the speed of light. Thomas Edison called experimentation his development of an invention through the building and testing of a series of models. So, both scientists and inventors experiment. They are not discovering the “secrets of nature”: they are observing how artifacts – their physical creations – behave. These physical models of thought reflect the characteristics of the tools with which they were made. They are socially constructed, as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0269889700000491
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  • 9
    Electronic Resource
    Electronic Resource
    The Professional Inventor in the Heroic Age: Elmer Sperry in Brooklyn (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 424 (1984), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1984.tb23500.x
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  • 10
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    "Edison: a Biography" by Matthew Josephson (Book Review) (1960)
    Detroit, Mich. : Periodicals Archive Online (PAO)
    Technology and Culture. 1:3 (1960:Summer) 284 
    Details
    ISSN: 0040-165X
    Topics: Technology
    Notes: BOOK REVIEWS
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:5129-1960-001-03-000019
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