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  • 11
    Electronic Resource
    Electronic Resource
    Relativistic particle dynamics in a steepening magnetosonic wave (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 1001-1010 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Acceleration of both electrons and ions to relativistic energy by large amplitude magnetosonic waves is investigated by use of numerical simulation. Nonlinear effects are shown to form the saturation mechanism and limit the amplitude below the level where a particle specie can undergo unlimited acceleration, which is expected theoretically. Spiky structures appear both in density and field waveforms that are characteristics of the relativistic regime. Both electrons and ions are strongly accelerated by Elx×Bz drift and Ety field, but their resonance features versus fields are strongly different. Around the trapping time, relativistic electron solitonlike wavelets are triggered from the main wave ramp; a few mechanisms are proposed for their interpretation. Both electrons and ions are strongly heated at the expense of the wave energy. This damping in association with the large space charge effects resulting from the spiky structures is the origin of some observed saturation level in the field energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859021
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    Paper (German National Licenses)
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  • 12
    Electronic Resource
    Electronic Resource
    Electrostatic instabilities of velocity-space-shell distributions in magnetized plasmas (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 2569-2579 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron instabilities of magnetized spherical shell distributions in velocity space with a colder Maxwellian background are investigated analytically with simulations using electrostatic particle codes. The resonant and nonresonant instabilities observed in the particle simulations are in agreement with zeros of the dielectric function, as found from the resonant approximation for waves with an electric field component along the magnetic field or by computation with a root solver code in the case of perpendicular propagation. Saturation of the instabilities is by nonlinear cyclotron resonance with the cold background in the resonant case or by nonstochastic cyclotron harmonic damping by the cold background in the nonresonant case. Instabilities invariably lead to perpendicular acceleration and heating of the cold background to velocities sometimes exceeding the shell velocity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865549
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    Paper (German National Licenses)
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  • 13
    Electronic Resource
    Electronic Resource
    Particle simulation of the magnetized rf plasma sheath (1992)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 2699-2704 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the sheath regions strong electric fields can develop that accelerate ions to sufficient energy to cause sputtering and increase the plasma impurities to an intolerable level. Simulations of these sheaths are performed with a one-and-two-half-dimensional (y,vx,vy,vz) electrostatic particle model with a homogeneous magnetic field tilted in relation to y; guiding-center electrons and full dynamic ions are used. The plasma is taken to be bounded by metallic walls in which a time-dependent potential difference V(t) is applied and the average energies and flux of ions hitting the walls are computed. The results show that the magnetic fields inhibits the sputtering caused by D atoms. Comparisons of the present model with previous work, which used a Vlasov model and fluid approach, are also made with good agreement in the appropriate regime.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860139
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  • 14
    Electronic Resource
    Electronic Resource
    Unified theory and comparative study of cyclotron masers, ion-channel lasers, and free electron lasers (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1270-1278 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A unified small-signal amplification theory is developed to compare growth mechanisms responsible for a number of relativistic radiation generators. The theory is formulated from the basis that the electron resonance frequency produced by the external fields of the devices depends on γ−q, where γ is the beam Lorentz factor and q is a constant (q=1 for cyclotron masers, q=1/2 for ion-channel lasers, and q=0 for free electron lasers). It is concluded that for wave amplification, the sign of the electron mismatch frequency is required to be the same as the sign of bunching parameter that is determined by the total bunching both axial and azimuthal; this depends on the q value. The two bunching mechanisms exist, not only in the single electron resonance regime, but also in the collective gain regime. Competition or reinforcement between the two bunching mechanisms is determined by the q value, the electron axial velocity, and the wave phase velocity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859819
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    Paper (German National Licenses)
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  • 15
    Electronic Resource
    Electronic Resource
    Self-consistent study of a perpendicular collisionless and nonresistive shock (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 1767-1788 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Particle dynamics and field behavior associated with a perpendicular collisionless supercritical and viscous shock are investigated by use of numerical simulation. A one-dimensional, relativistic, fully electromagnetic and nonperiodic particle simulation code (for both electrons and ions) is used where self-consistent space-charge effects and induced effects are totally included. The principal field patterns of the shock (trailing wave train, ramp, and foot region) are studied in detail and are shown to have scale lengths mainly dictated by ion dynamics; the behavior of the corresponding plasma currents associated with the different field components is also presented. Ions are shown to suffer successive "acceleration–trapping–detrapping'' at the shock front, and locally in the trailing wave train of the downstream region through combined effects of the electrostatic and magnetic fields. While detrapped, the reflected ions describe very large Larmor orbits and cause a ring distribution; a large rapid nonstochastic ion heating results from this ion gyration. This heating (resistivity-free) is the main source of dissipation and is responsible for large field damping. Competitive effects such as particle stochasticity, particle trapping, wave damping, wave overtaking, and dispersion effects are shown to interact with each other and to affect the overall dissipation mechanism. Comparison with previous works is also discussed. Various Mach number situations are considered, leading to the definition of a transitory regime between subcritical and supercritical regimes and of a corresponding critical threshold of the electrostatic field. In contrast with the supercritical regime, the subcritical regime is characterized by a low density of trapped-reflected ions, a broad ion distribution function with a weak tail, and a weak adiabatic bulk ion heating.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866191
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    Paper (German National Licenses)
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  • 16
    Electronic Resource
    Electronic Resource
    Stability of the low-frequency hot-electron interchange mode for a bumpy torus simulation model (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 3237-3244 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The parametric dependence of the growth rate of the low-frequency hot-electron interchange mode is studied with a two-and-a-half-dimensional relativistic electromagnetic particle code that models the geometry of a bumpy torus. The simulation results are compared in detail with finite-Larmor-radius theory, as well as zero-Larmor-radius theory. For the long-wavelength modes, the growth rates measured in the simulations tend to agree with those predicted from zero-Larmor-radius theory. For short-wavelength modes, the stabilizing effects of finite Larmor radius are significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866498
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    Paper (German National Licenses)
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  • 17
    Electronic Resource
    Electronic Resource
    Upgrading Miskolc Sewage-Treatment Works, Hungary (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 7 (1993), S. 0 
    Details
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Traditionally, sewage-works design in Hungary has been based on rigid national standards with little consideration being given to the requirements of individual situations. This has resulted in plants that performed poorly and were expensive to construct and operate.The paper describes measures to improve the environment by upgrading Miskolc sewage-treatment works, and the conflict between the cost of those facilities, and the ability to pay against a background of changing economic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1747-6593.1993.tb00842.x
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  • 18
    Electronic Resource
    Electronic Resource
    Self-consistent plasma heating and acceleration by strong magnetosonic waves for θ=90 °. Part I: Basic mechanisms (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 821-836 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The behavior of strong magnetosonic waves propagating perpendicular to a static field B0 is investigated within the frequency range ωci〈ω〈ωlh; ωci,ω, and ωlh are, respectively, the ion cyclotron, the pump wave, and the lower-hybrid frequencies. A one-dimensional, relativistic, fully electromagnetic, particle simulation code (for both electrons and ions) is used, where self-consistent effects are totally included. During the buildup phase, a longitudinal electric field develops and attains a nonlinear level which strongly distorts its shape so that many harmonics are produced. This is followed shortly by ion trapping, which simultaneously enhances the wave overtaking (the wave crests overtaking the wave troughs) and produced a strong wave damping. A very large ion acceleration accompanied by a strong heating (mainly nonstochastic) perpendicular to B0 results; the electrons exhibit only poor heating associated with their adiabatic compression. The dynamics of both particle species, the consequences of the wave–particle energy transfer and the particle viscosities, are studied in detail. Competitive and self-consistent effects such as space-charge effects, wave overtaking, ion trapping, and wave damping are investigated and compared with previous models; the mechanisms by which these various phenomena interact on each other are analyzed. Characteristics of nonstochastic and stochastic ion heating are also discussed. Our computations show that if sufficient intensity is reached, one is not constrained to use lower-hybrid waves or cyclotron harmonic waves to heat a plasma efficiently and that any frequency below ωlh can be used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865939
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    Paper (German National Licenses)
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  • 19
    Electronic Resource
    Electronic Resource
    Water Quality and Management Strategies in London's Docklands (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 6 (1992), S. 0 
    Details
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Regeneration and changes in land use in London's Docklands have resulted in new water quality requirements. Areas previously occupied by docks now form part of redevelopment projects which have made a feature of the water.The paper describes a project to provide water that is aesthetically pleasing and of a quality suitable for water contact recreational activities.An extensive programme of water sampling and analysis was carried out to gain an understanding of the processes affecting water quality, including the monitoring of algal growth. The river is the main source of nutrients in the docks, which results in large concentrations of algal biomass and bacterial contamination. The principal strategy is to limit light via artificial mixing systems supplemented by limiting the inflow of nutrients from the river.The results from the water sampling programme have been used to build a 3D computer model with a supporting graphic information system to attain (a) qualitative evaluations of management and development options, and (b) short-term predictions of changes in water quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1747-6593.1992.tb00753.x
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  • 20
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    Forster, "The Counter-Reformation in the Villages: Religion and Reform in the Bishopric of Speyer, 1560-1720" (Book Review) (1994)
    Oxford : Periodicals Archive Online (PAO)
    German history. 12:2 (1994:June) 260 
    Details
    ISSN: 0266-3554
    Topics: History
    Notes: BOOK REVIEWS
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:f162-1994-012-02-000015
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