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  • 1
    Electronic Resource
    Electronic Resource
    The Alfvén-Carlquist double-layer theory of solar flares (1978)
    Springer
    Astrophysics and space science 56 (1978), S. 89-107 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use the Vlasov equations for ions and electrons to develop a theory of a double layer in which there are both free and trapped electrons and ions. We find the equations which replace the Langmuir condition and the Bohm conditions and by numerically solving the resultant differential equation we find for particular choices of distribution functions the potential distribution in the layer. We discuss the applicability of this theory to solar flares, and show that conditions in solar flares may be such that double layers can exist for which the free particles have a power-law energy distribution. These particles will be accelerated in a double layer and may in this way account for the production of high-energy particles during the impulsive phase of solar flares.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00643464
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  • 2
    Electronic Resource
    Electronic Resource
    Faraday rotation and the turbulent structure of the Galaxy (1977)
    Springer
    Astrophysics and space science 51 (1977), S. 385-393 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We extend Jokipii and Lerche's analysis of the turbulent structure of our Galaxy by means of a study of the rotation measure of extragalactic sources. Like them we use a simple, statistically homogeneous and isotropic disc model of the Galaxy and assume that the magnetic field has both an average component and a fluctuating one. We assume that the electron density is proportional to some power of the magnetic field (N eαB n with 1≤n≤2). Using the rotation measure data on 242 extragalactic sources given by Vallée and Kronberg we consider both an exponential and a Gaussian two-point correlation function for the (Gaussian) fluctuating component of the magnetic field with a correlation lengthL. We find reasonable agreement between theory and observations for an average magnetic field of about 3 μG, a fluctuating magnetic field component with an amplitude of about 2.6μG, an average electron density of about 0.03 cm−3, a fluctuating density component of about 0.05 cm−3, and a correlation length of about 300 pc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644160
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  • 3
    Electronic Resource
    Electronic Resource
    The diffusion model of cosmic-ray propagation (1979)
    Springer
    Astrophysics and space science 61 (1979), S. 3-17 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We show that the observational data on galactic synchrotron radiation can be explained if there is a break in the electron spectrum at about 2 GeV. We also show that one can explain the occurrence of that break by carefully considering the time evolution of the high-energy electron spectrum in supernova remnants, taking into account synchrotron losses, adiabatic expansion and diffusive losses from the remnant. The model considered is also in agreement with the observed radio spectrum of Cas A and the decay rate of its flux density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645788
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  • 4
    Electronic Resource
    Electronic Resource
    The diffusion model of cosmic-ray propagation (1979)
    Springer
    Astrophysics and space science 61 (1979), S. 45-64 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The diffusion equation for the electron component of cosmic rays is solved and the solution obtained is used to evaluate the electron spectrum, its spatial distribution, and the distribution of the galactic synchrotron radiation. We find reasonable agreement between theory and observational data for the same values of the parameters as found in Part II.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645790
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  • 5
    Electronic Resource
    Electronic Resource
    The diffusion model of cosmic-ray propagation (1979)
    Springer
    Astrophysics and space science 61 (1979), S. 19-44 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We set up diffusion equations for the nuclear component of cosmic rays and solve these to find the ratio of light to medium nuclei in the cosmic rays as well as the gamma-ray distribution in our Galaxy. From a comparison of our calculated quantities with observational data we determine the values of various parameters appearing in the model. We find that best agreement between theory and observations is obtained if the cosmic-ray confinement region consists of a narrow disk of total height 160 pc and radius 16 kpc, where the cosmic-ray sources are located, and an extensive halo of height 20 kpc. The diffusion coefficient near the Sun must be between 1026 and 1027 cm2 s−1 while it equals 1028 to 1029 cm2 s−1 in the halo. Finally, we find that the diffusion coefficient in the Galaxy must depend on the gas density as a power law with an index of the order of −1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645789
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  • 6
    Electronic Resource
    Electronic Resource
    A green function approach to the paramagnetic phase of a Heisenberg ferromagnet (1969)
    Springer
    Journal of statistical physics 1 (1969), S. 149-161 
    Details
    ISSN: 1572-9613
    Keywords: Paramagnetic phase of Heisenberg ferromagnet ; Green function methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A higher-order decoupling similar to the first-order Bogolyubov-Tyablikov decoupling is used to find various correlation functions in the paramagnetic region for a Heisenberg ferromagnet. Expressions are given for the susceptibility, the nearest-neighbor correlation, and autocorrelation at the critical point as well as at high temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007247
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  • 7
    Electronic Resource
    Electronic Resource
    On the convection of a passive scalar by a turbulent Gaussian velocity field (1991)
    Springer
    Journal of statistical physics 63 (1991), S. 305-313 
    Details
    ISSN: 1572-9613
    Keywords: Turbulence ; diffusion ; helicity ; convection ; incompressible fluids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Through the use of the Novikov-Furutsu formula for Gaussian processes an equation is obtained for the diffusion of the ensemble average of a passive scalar in an incompressible turbulent velocity field in terms of the two-point, two-time correlator of this field. The equation is valid for turbulence which is not necessarily homogeneous or stationary and thus generalizes previous work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01026606
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  • 8
    Electronic Resource
    Electronic Resource
    On the limiting polarization of radio-waves (1973)
    Springer
    Astrophysics and space science 20 (1973), S. 39-42 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We discuss the limitations of various expressions governing the determination of the limiting polarization of radio-waves and slightly extend earlier work, which was limited to the case where the wave-vector is parallel to the density gradient, to the special case where the magnitic field is parallel to the density gradient, but the wave-vector can be at an angle to both. We consider the problem especially in connection with the problem of pulsar emission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645582
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  • 9
    Electronic Resource
    Electronic Resource
    Formation of the regular satellite systems and rings of the major planets (1979)
    Springer
    Earth, moon and planets 21 (1979), S. 43-62 
    Details
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract In this paper, we apply the ideas presented by one of us (Prentice, 1978a, b) for the development of the proto-solar cloud into a system of Laplacian rings to the development of the protoplanetary clouds which ultimately led to Jupiter, Saturn and Uranus. We show that if one accepts this scenario — especially the idea of supersonic turbulence in the proto-planetary clouds — one can satisfactorily explain, on the basis of fixing a single adjustable parameter, both the geometric precession of the orbital radii of the regular satellite systems of these three planets and the chemical composition and mass distribution of these satellites. We suggest that thermal stirring in the proto-planetary cloud in the vicinity of the surface of the planet may be responsible for the smaller masses of some of the inner satellites as well as for the formation of the rocky rings of Uranus. The icy rings of Saturn are suggested to be the product of condensation processes in a continuous gaseous disc within the Roche limit of the planet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00897054
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  • 10
    Electronic Resource
    Electronic Resource
    Fluctuations in the population of the ground state of Bose Systems (1970)
    Springer
    Journal of statistical physics 2 (1970), S. 329-346 
    Details
    ISSN: 1572-9613
    Keywords: Fluctuations ; Bose systems ; saddle-point method applications ; Einstein condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Formulas are given which show how the fluctuations of the ground-state occupation number in a Bose System are strongly suppressed at low temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020442
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