ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The operation of a uniformly insulated extraction applied-B ion diode (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2555-2561 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the first experimental results of a uniformly insulated extraction applied-B ion diode. The diode typically attained beam generating efficiencies of 70% at the time of peak beam power. This is a significant improvement over previous extraction applied-B ion diodes, demonstrating the importance of uniform insulation as suggested by theory [J. Appl. Phys. 59, 2685 (1986)]. Furthermore, we found that the beam current is nearly independent of the ion-emitting area down to a minimum area. At the minimum area, the beam current density was enhanced by 150 times the monopolar Child–Langmuir value. This data supports a recently proposed theory [Phys. Rev. Lett. 59, 2295 (1987)] that predicts large enhancements due to the electron diamagnetic effect on the virtual cathode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346479
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    High-temperature superconducting vector switch : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4910-4912 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The feasibility of a high-temperature superconducting switch based on the principle of the superconducting vector switch (SVS) is discussed. This switch exploits the anisotropy in electrical conductivities of the high-temperature superconductors. Underlying the SVS mechanism is the ability to turn on/off large superconducting currents confined to the CuO2 planes that characterize these materials using lower currents flowing normal to the planes. The required conditions to optimize the switch and increase the gain are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348224
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    First-principles calculations of chemical and magnetic correlations in Fe-13.5% V (abstract) : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 6151-6151 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have developed an ab initio method for calculating the static correlation functions in substitutional alloys, which, for example, describes their atomic short-range order (ASRO) as given by atomic diffuse scattering intensities. For magnetic alloys, a contribution to the total diffuse scattering intensities also results from the moment-chemical correlations (i.e., variations of local moments due to changes in the chemical environment). The response functions, which may be directly compared to single crystal neutron-scattering, are derived from a mean-field statistical mechanical description of compositional fluctuations in alloys. The statistical averages are performed via the Korringa–Kohn–Rostoker coherent-potential approximation, which incorporates the electronic structure of the high-temperature, chemically disordered state. For magnetic Fe-13.5% V alloys, we present results of first-principles calculations of the ASRO, which compare very well with the (quenched) single crystal data obtained by Cable et al.,1 and predict the structure of the moment-chemical correlations. Moreover, we determine the origin of the q-dependent structure in these correlations. In the future, this will allow direct comparison of neutron data with theory to understand more fully the underlying mechanisms which drive, e.g., ASRO.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348788
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Magnetic properties and microstructure of Fe4N and (Fe,Ni)4N : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6247-6249 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-phase Fe4N and (Fe1−xNix)4N compounds have been synthesized in a continuous form by heat treating iron and iron-nickel alloy sheets at various temperatures under NH3/H2 atmospheres. The Fe4N sheet has a high room-temperature magnetization value of 179 emu/g (2.14 μB/Fe), which is only slightly less than 218 emu/g (2.19 μB/Fe) observed in pure iron. The magnetic moments of the Fe-Ni alloy nitrides decreased monotonically as x was increased, in contrast to those for the starting alloys Fe1−xNix which exhibited a peak value around x=0.05. The decrease in magnetic moment with nickel content in the alloy nitrides was close to the value anticipated by magnetic dilution from nickel. The coercive force is about 5 Oe and is slightly decreased by the Ni substitution. The Fe-nitride offers a significantly improved corrosion resistance over pure iron. Even further improvement is obtained in the (Fe1−xNix)4N system with only slight sacrifice in magnetic moment. The addition of nickel has been found to noticeably improve the mechanical ductility of the normally brittle Fe4N compound. Theses nitrides also exhibit significantly increased electrical resistivity and wear resistance, and may be useful for a variety of technological applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Electron–anode interactions in particle-in-cell simulations of applied-B ion diodes (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 3369-3387 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Particle-in-cell simulations of applied-B ion diodes using the QUICKSILVER code [D. B. Seidel et al., in Proceedings of the Europhysics Conference on Computational Physics, Amsterdam, 1990, edited by A. Tenner (World Scientific, Singapore, 1991), p. 475] have been augmented with Monte Carlo calculations of electron–anode interactions (reflection and energy deposition). Extraction diode simulations demonstrate a link between the instability evolution and increased electron loss and anode heating. Simulations of radial and extraction ion diodes show spatial nonuniformity in the predicted electron loss profile leading to hot spots on the anode that rapidly exceed the 350 °C–450 °C range, known to be sufficient for plasma formation on electron-bombarded surfaces. Thermal desorption calculations indicate complete desorption of contaminants with 15–20 kcal/mole binding energies in high-dose regions of the anode during the power pulse. Comparisons of parasitic ion emission simulations and experiment show agreement in some aspects, but also highlight the need for better ion source, plasma, and neutral gas models. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873576
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The role of the neutral beam fueling profile in the performance of the Tokamak Fusion Test Reactor and other tokamak plasmas : The 38th annual meeting of the Division of Plasma Physics (DPP) of the American Physical Society (1997)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 4 (1997), S. 1699-1706 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Scalings for the stored energy and neutron yield, determined from experimental data, are applied to both deuterium-only and deuterium–tritium plasmas in different neutral-beam-heated operational domains in the Tokamak Fusion Test Reactor [Nucl. Fusion 25, 1167 (1985)]. The domain of the data considered includes the Supershot, high poloidal beta, low-mode, and limiter high-mode operational regimes, as well as discharges with a reversed magnetic shear configuration. The new important parameter in the present scaling is the peakedness of the heating beam fueling profile shape. Ion energy confinement and neutron production are relatively insensitive to other plasma parameters compared to the beam fueling peakedness parameter and the heating beam power when considering plasmas that are stable to magnetohydrodynamic modes. However, the stored energy of the electrons is independent of the beam fueling peakedness. The implication of the scalings based on this parameter is related to theoretical transport models such as radial electric field shear and ion temperature gradient marginality models. Similar physics interpretation is provided for beam heated discharges on other major tokamaks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.872272
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ion divergence in magnetically insulated diodes (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 2175-2182 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetically insulated ion diodes are being developed to drive inertial confinement fusion. Ion beam microdivergence must be reduced to achieve the very high beam intensities required to achieve this goal. Three-dimensional particle-in-cell simulations [Phys. Rev. Lett. 67, 3094 (1991)] indicate that instability-induced fluctuations can produce significant ion divergence during acceleration. These simulations exhibit a fast growing mode early in time, which has been identified as the diocotron instability. The divergence generated by this mode is modest, due to the relatively high-frequency ((approximately-greater-than)1 GHz). Later, a low-frequency low-phase-velocity instability develops with a frequency that is approximately the reciprocal of the ion transit time. This instability couples effectively to the ions, and can generate unacceptably large ion divergences ((approximately-greater-than)30 mrad). Linear stability theory reveals that this mode has structure parallel to the applied magnetic field and is related to the modified two-stream instability. Measurements of ion density fluctuations and energy-momentum correlations have confirmed that instabilities develop in ion diodes and contribute to the ion divergence. In addition, spectroscopic measurements indicate that lithium ions have a significant transverse temperature very close to the emission surface. Passive thin-film lithium fluoride (LiF) anodes have larger transverse beam temperatures than laser-irradiated active sources. Calculations of the ion beam source divergence for the LiF film due to surface roughness and the possible loss of adhesion and fragmentation of this film are presented. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871672
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Isotopic scaling of confinement in deuterium–tritium plasmas (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 2299-2307 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The confinement and heating of supershot plasmas are significantly enhanced with tritium beam injection relative to deuterium injection in the Tokamak Fusion Test Reactor [Plasma Phys. Controlled Fusion 26, 11 (1984)]. The global energy confinement and local thermal transport are analyzed for deuterium and tritium fueled plasmas to quantify their dependence on the average mass of the hydrogenic ions. Radial profiles of the deuterium and tritium densities are determined from the D–T fusion neutron emission profile. The inferred scalings with average isotopic mass are quite strong, with τE∝〈A〉0.85±0.20, τEthermal∝〈A〉0.89±0.20, χitot∝〈A〉−2.6±0.5, and De∝〈A〉−1.4±0.2 at fixed Pinj. For fixed local plasma parameters χitot∝〈A〉−1.8±0.4 is obtained. The quoted 2σ uncertainties include contributions from both diagnostic errors and shot irreproducibility, and are conservatively constructed to attribute the entire scatter in the regressed parameters to uncertainties in the exponent on plasma mass. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871253
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Study of the effect of compressional Alfvén modes on thermal transport in the National Spherical Torus Experiment : Review,Tutorial and Invited Papers from the 43rd Annual Meeting of the APS Division of Plasma Physics (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 2069-2076 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: With the first injection of neutral beams into the National Spherical Torus Experiment (NSTX) [Ono et al., Nucl. Fusion 40, 557 (2000)], a broad spectrum of fluctuations consisting of nearly equally spaced peaks in the frequency range from about 0.2 to 1.2 times the ion cyclotron frequency was observed. The frequencies scale with toroidal field and plasma density consistently with Alfvén waves. From these and other observations, the modes have been identified as compressional Alfvén eigenmodes (CAE). It has also recently been found that the ratio of the measured ion and electron temperatures in NSTX during neutral beam heating is anomalously high [Bell, Bull. Am. Phys. Soc. 46, 206 (2001)]. To explain the anomaly in the ratio of ion to electron temperature, it has been suggested that the CAE, driven by the beam ions, stochastically heat the thermal ions [Gates et al., Phys. Rev. Lett. 87, 205003 (2001)]. In this paper it is shown through studies of the power balance that stochastic heating of the thermal ions by the observed CAE alone is not solely responsible for the anomaly in the ion to electron temperature ratio. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1464542
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Enhancement of Tokamak Fusion Test Reactor performance by lithium conditioning (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 1892-1897 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Wall conditioning in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire et al., Phys. Plasmas 2, 2176 (1995)] by injection of lithium pellets into the plasma has resulted in large improvements in deuterium–tritium fusion power production (up to 10.7 MW), the Lawson triple product (up to 1021 m−3 s keV), and energy confinement time (up to 330 ms). The maximum plasma current for access to high-performance supershots has been increased from 1.9 to 2.7 MA, leading to stable operation at plasma stored energy values greater than 5 MJ. The amount of lithium on the limiter and the effectiveness of its action are maximized through (1) distributing the Li over the limiter surface by injection of four Li pellets into Ohmic plasmas of increasing major and minor radius, and (2) injection of four Li pellets into the Ohmic phase of supershot discharges before neutral-beam heating is begun. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871984
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...