Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 1699-1709 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Localized longitudinal space-charge waves in a transport channel with a resistive wall are investigated experimentally. The space-charge waves with various pulse widths are generated in electron beams with energies of 3.0–8.5 keV and currents of 30–135 mA, and they are transported through a resistive channel with a resistance of 5–10 kΩ and a length of 1 m. The resistive channel, made of a glass tube with a resistive material coating, is surrounded by a long solenoid which provides the focusing for the beam. The localized space-charge waves are measured with current monitors and energy analyzers at the entrance and exit of the resistive channel, and the wave-amplitude growth and damping rates are determined. The measured results are compared with the theory in the long-wavelength range. For localized waves with short widths, where the long-wavelength approximation is not valid any more, dispersion and distributed capacitance effects on the growth/damping rates are discussed. In addition, preliminary results on the energy width measurements of space-charge waves are presented. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 111-121 
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Both Zakharov equations and Vlasov equations are solved numerically to study the strong Langmuir turbulence developed in a plasma driven by an external pump field oscillating at the plasma frequency. A steady state turbulence in Vlasov simulations is reached by using open boundary conditions under which hot particles generated by strong caviton fields are replaced by initial cold Maxwellian particles when they cross the boundaries of simulation domain. A similar steady turbulent state in Zakharov simulations is easily achieved by implementing a phenomenological damping model and using periodic boundary conditions. Simulation results of these two different models are compared and investigated. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 2064-2070 
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Space-charge effects and collective behavior play an important role in the dynamics of intense beams for accelerator applications. One of the research issues is the longitudinal space-charge waves and instabilities in high current accelerators. At the University of Maryland, an experimental program has been conducted to systematically study space-charge waves and longitudinal instabilities in space-charge dominated electron beams. This includes the generation of localized space-charge waves in an active device; the propagation and end reflection of space-charge waves in a conducting transport channel; and the longitudinal instabilities in a resistive-wall channel. This paper reports and discuss our experimental results. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 1129-1139 
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Vlasov simulations are developed to study the one-dimensional modulational instability and Langmuir collapse in a plasma driven by an external field. Both electrons and ions in the plasma are described by the Vlasov equations. The external driving field energy density is ∼10−3 times the initial electron thermal energy density. The plasma has a mass ratio of mi/me=1836, and a temperature ratio of Ti/Te=0.1 or 1.0, where mi, me, Ti, and Te are the ion mass, electron mass, ion temperature, and electron temperature. The modulational instability is saturated by the formation of Langmuir cavitons which later collapse and burn out due to the strong wave–particle interactions. The particle heating during a single Langmuir collapse is small under this weak driving field. The accelerated electron and ion jet-like streams in phase space as well as the nucleation of cavitons are observed during the evolution. Zakharov equations with the same parameters and similar initial conditions are also simulated, and the results are compared with those of the Vlasov simulations. The two models agree with each other quantitatively up to the first collapse following the saturation of exponential growth; dynamic differences appear after the first collapse. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 669-672 
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The properties of solitary waves in space-charge dominated charged particle beams are investigated theoretically. Similarly to linear space-charge waves, both slow and fast solitary waves can exist. In a dissipative environment, e.g. a resistive-wall channel, it is shown that the slow space-charge solitary waves grow in amplitude, while the fast space-charge solitary waves decay. However, the growth and decay rates differ from those of the linear waves. A possible experiment with an electron beam is proposed to demonstrate these phenomena. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of materials science 33 (1998), S. 2563-2571 
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Stress-induced γ→α2, α2→γ and γ→9R phase transformations in a hot-deformed Ti–45 at% Al–10 at% Nb alloy have been investigated using high-resolution transmission electron microscopy. The γ→α2 phase transformation is an interface-related process. The interfacial superdislocations emitted from the misoriented semicoherent α2–γ interface react with each other or with the moving dislocations in the γ phase, resulting in the formation of the α2 phase. The nucleation of the α2→γ phase transformation takes place either at the α2–γ interfaces or at the stacking faults on the basal plane of α2 phase, and the growth of γ plate is accomplished by the moving of a/6〈1 0 1 0〉 Shockley partials on alternate basal plane (0 0 0 1)α2. The 9R structure was usually found to form at incoherent twin or pseudotwin boundaries. During deformation the interfacial Shockley partial dislocations of these incoherent twin and pseudotwin boundaries may glide on (1 1 1)γ planes into the matrix, resulting in the formation of 9R structure. The interfaces (including α2–γ and γ–γ interfaces) as well as the crystallographic orientation relationship between the as-received or stress-induced α2, γ and 9R phase have been analysed. The mechanisms for the stress-induced γ→α2, α2→γ and γ→9R phase transformations were also discussed. © 1998 Chapman & Hall
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    The European physical journal 5 (1999), S. 167-171 
    ISSN: 1434-6079
    Schlagwort(e): PACS. 34.80.Kw Electron-ion scattering; excitation and ionization - 34.80.Dp Atomic excitation and ionization by electron impact
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract: A simplified relativistic configuration interaction method is used to study the dielectronic satellite transition processes. In this method, the infinite resonant doubly excited states can be calculated, and furthermore, the whole high-n dielectronic satellite transition processes can be treated conveniently by interpolation (rather than extrapolation) in the frame of Quantum Defect Theory. As an example, we calculate the contributions from high-n dielectronic satellites to the resonance line in helium-like iron, and the results are in good agreement with the experimental measurements.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    The European physical journal 2 (1998), S. 231-235 
    ISSN: 1434-6079
    Schlagwort(e): PACS. 34.80.Kw Electron-ion scattering; excitation and ionization - 34.80.Dp Atomic excitation and ionization by electron impact
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract: A simplified relativistic configuration interaction method is used to calculate the dielectronic recombination cross sections and rate coefficients for heliumlike carbon. In this method, the infinite resonant doubly excited states can be treated conveniently in the frame of Quantum Defect Theory. Our calculated cross sections are in agreements with the experimental measurements except for the 1s2lnl'(n=6,7) resonances. The total energy-integrated cross sections and rate coefficients over all dielectronic resonances are in agreements with the experimental measurements within percent.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...