Library

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
    Numerical simulation of Cerenkov whistler emission by a modulated beam (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 1 (1994), S. 4082-4088 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Through Cerenkov emission, the interaction of an electron beam with a plasma leads to the excitation of whistler waves. Particle-in-cell simulations show that, when the beam is injected at an angle with respect to the magnetic field, the whistler wave emission of a modulated beam is increased compared to the same beam without modulation. This increased emission is related to the transfer of energy which occurs between the electrostatic mode directly excited by the density modulation and the electromagnetic whistler. This transfer of energy requires that the electrostatic field has a component perpendicular to the magnetic field. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.870877
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Plasma heating through a supercritical oblique collisionless shock (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 1110-1114 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron and ion dynamics are investigated through particle simulation of a supercritical oblique collisionless shock. As θ deviates from 90°, ions are accelerated and trapped in the electrostatic wells and later become detrapped; this results in strong ion heating perpendicular to B0. Below a critical angle θte electrons are strongly energized along B0, and heated. A large parallel electron current builds up and induces new transverse electromagnetic components in the ramp of the shock. For weaker angles, ion heating vanishes below a second critical angle θti.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Hybrid and particle simulations of an interface expansion and of collisionless shock: A comparative and quantitative study (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 3967-3981 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The release of a hot and dense drifted plasma into a background ambient magnetoplasma is analyzed with the help of one-dimensional hybrid and full particle electromagnetic simulations, in conditions approaching those commonly met in laboratory experiments. The overall study is mainly focused on the early times of the interaction between both plasmas and for a strictly perpendicular expansion in the magnetic field. Two successive regimes are evidenced: a "transitory" regime, where a characteristic interface builds up, followed by a second regime, where a shock forms. Our purpose in this study is to analyze in detail the differences inherent to each code, and to quantify their impact on the corresponding simulation results. Several difficulties are identified throughout this comparison, since different assumptions are used within each code; a method based both on the best time/space scale lengths fit and on a judicious choice of plasma and numerical parameters is proposed in order to overcome these difficulties. The present results and a similar comparative method may be easily extended when analyzing the dynamics of the interface expansion building up in laboratory plasmas (during experiments of laser–target interactions), in space plasma (active experiments), and when applied to open questions related to collisionless shocks. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1389862
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Electrostatic radiation in a hot magnetoplasma: Intrinsic diffraction or interference effects? (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 2755-2772 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Several experiments have evidenced oscillatory patterns of the electrostatic potential radiated by a small antenna in a hot magnetoplasma. Several previous interpretations based on analytical calculations and numerical computations are discussed; they are found not to be exhaustive or completely satisfactory. A new mechanism responsible for these structures is proposed. It consists of a filtering by the plasma of the wave vectors of the radiated waves. This mechanism is caused by the existence of a restricted range of undamped wave vectors surrounded by highly damped ones. This phenomenon, presently named "intrinsic diffraction,'' is used to interpret both the spatial oscillations of the potential around the resonance cone when ω〈min(ωp, ωc) and around the direction perpendicular to the magnetostatic field when nωc〈ω〈(n+1)ωc; ω, ωp, ωc are, respectively, the wave, the plasma, and the electron-cyclotron frequencies, and n is any positive integer. The results of both analytical calculations and numerical computations are found to be in good agreement within the two frequency ranges. The location and the amplitude of the oscillatory structure are simply related to the width of the domain of unattenuated wave vectors. New diagnosis methods for the plasma temperature are suggested from this model. Additional directivity and curvature effects related to the topology of the wavenumber surfaces are discussed. The generalization of the use of the intrinsic diffraction picture is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865235
    Library Location Call Number Volume/Issue/Year 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...