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  • 1980-1984  (5)
  • 1965-1969  (1)
Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 79 (1981), S. 67-75 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The reciprocal influence of the electrons and protons, on one side, and the α-particles, on the other side in the quiet solar wind is investigated within the framework of a conductive three-fluid model (with frictional forces included). For this purpose two mathematical methods are used, namely: I. Simultaneous solution of the fluid equations for all three species; and II. Solution of two-fluid equations (for electrons and protons) followed by that of a ‘modified’ one-fluid equation for the α-particles (in which the two-fluid solutions are used for electrons and protons). The results of our investigation indicate the following: (a)The macroscopic α-particle characteristics as obtained from the two methods of solution are almost identical. Thus, the differences between the ‘three-fluid’ and ‘two-fluid’ characteristics of the electrons and protons represent a second order (and negligible) effect on the α-particle characteristics. In both approaches, the frictional interaction between α-particles and protons raises the (lower) α-particle streaming velocity to that of the protons and decreases the relative α to proton density ratio to a value about 0.035, as observed at 1 AU, (b)The electron and proton characteristics obtained from ‘three-fluid’ and ‘two-fluid’ solutions are similar, except for the proton temperature. The ‘two-fluid’ solution providesT p-values which, though within the observational error, are larger than those obtained from the simultaneous three-fluid solution (at 1 AU, the difference amounts to about 30%). Thus, the α-particles affect the temperature profile of the protons in the solar wind through heat exchange (mainly), dynamical friction, as well as through their contribution to the interplanetary electrostatic field.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1572-9613
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 5 (1969), S. 333-341 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The anomalous Doppler-shift interaction between positive ions and right-hand (RH) polarized E.M. waves propagating at a small angle to a static magnetic field is investigated. The linear rate of growth of the resulting instability is obtained and compared with the growth rate for the parallel propagation case. For conditions typical of the solar wind at about 1 AU, the rate of growth always decreases with increasing propagation angle. For very large ion pressures (β‖≫1) and temperature anisotropies (T ‖ T ⊥≫1), the rate of growth may increase with increasing propagation angle.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Space science reviews 26 (1980), S. 277-315 
    ISSN: 1572-9672
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Significant progress in the description and understanding of the solar wind has been achieved with fluid models. Nevertheless, there is — so far — no general model capable of providing a mathematical solution for the overall solar wind phenomenon. This paper attempts a presentation of existing plasma fluid models for the solar wind. This includes a general characterization and illustration of the capabilities of various models. Insight to fundamental physical processes is provided by such model comparisons. As a result, a sound basis is provided for further physical study of magnetohydrodynamic and/or transient phenomena, neither of which is systematically considered here.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Space science reviews 34 (1983), S. 63-72 
    ISSN: 1572-9672
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Some advances in the hydrodynamical large-scale theory, on the one hand, and in the kinetic theory, on the other hand, of the solar wind are reviewed. For brevity, we sketch the general frame, point out the problems and approaches and then illustrate by a few examples the ways in which progress has been achieved during the past four years.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1572-9613
    Schlagwort(e): Velocity distribution functions ; plasmas-nonequilibrium ; stellar systems-nonequilibrium ; weakly interacting many-body systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The most probable velocity distribution function of each component,f a , of a nonequilibrium multispecies spherically symmetric system of particles (stellar plasma atmospheres and winds, stellar systems, pellet-fusion systems) is analytically derived forthe case in which each component is described by the first six moments of f a . This is achieved by the aid of a variational approach based on the requirement that the BoltzmannH function for the system be a minimum, subject to the constraints provided by the sets of six macroscopic parameters describing the nonequilibrium state. The use of the so-obtained velocity distribution functions for the closure of the moment equations as well as for the calculation of their collisional terms (via the Fokker-Planck equation) is discussed. The limitations on the maximum deviations from the equilibrium state which are consistent with the assumptions used are also indicated.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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