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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 581 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 165-166 (1990), S. 489-490 
    ISSN: 0921-4526
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 165-166 (1990), S. 489-490 
    ISSN: 0921-4526
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied mechanics and technical physics 20 (1979), S. 328-333 
    ISSN: 1573-8620
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In the study of qualitative features of flow of a rarefied plasma over bodies in ionospheric aerodynamics, the problem of flow behind a two-dimensional plate is often considered. The formulation of this problem and its relation to flow over real objects was considered in detail in [1], This model problem has been analyzed in a number of papers using two main approaches: description of the flow with the help of the similarity solution found in [2, 3], and numerical solution of the equations of plasma motion [4–7]. A review of the main results obtained by the two methods can be found in [1, 6]. This paper gives a numerical solution of the problem of transverse supersonic flow over a flat plate. The plasma is assumed to be collisionless and is described by the kinetic equation with a self-consistent field. The particle-in-cell method is used to solve the kinetic equation. In contrast with most numerical calculations previously performed [4–6], the present paper considers the case, of greater practical interest, of flow over a body whose dimension R is much greater than the Debye radius Di in the unperturbed plasma. Practically all the known results for this case have been obtained using the similarity solution [2, 3], which is not valid, however, in the entire region of unperturbed flow, and therefore does not give a complete solution to the problem. Individual numerical calculations (see [7]) do not add much to the similarity analysis, since they refer to a very narrow range of the flow parameters. The main emphasis in the present paper is the study of wake structure behind a flat plate and plasma instability in the wake. The computations were performed in a wide range of variation of the ratioβ=Te/Ti, and one can follow the processes of ion acceleration, interaction of the accelerated group of ions with the plasma, development of beam-type instability [1, 8], and formation and decay of the turbulent wake. The qualitative wake structure features discussed below are also found, of course, in plasma flow over actual three-dimensional bodies.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Communications in mathematical physics 23 (1971), S. 185-188 
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 109 (1997), S. 309-355 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the thermodynamic behaviour of a Bose gas interacting with repulsive forces and confined in a harmonic anisotropic trap. We develop the formalism of mean field theory for non uniform systems at finite temperature, based on the generalization of Bogoliubov theory for uniform gases. By employing the WKB semiclassical approximation for the excited states we derive systematic results for the temperature dependence of various thermodynamic quantities: condensate fraction, density profiles, thermal energy, specific heat and moment of inertia. Our analysis points out important differences with respect to the thermodynamic behaviour of uniform Bose gases. This is mainly the consequence of a major role played by single particle states at the boundary of the condensate. We find that the thermal depletion of the condensate is strongly enhanced by the presence of repulsive interactions and that the critical temperature is decreased with respect to the predictions of the non-interacting model. Our work points out an important scaling behaviour exhibited by the system in large N limit. Scaling permits to express all the relevant thermodynamic quantities in terms of only two parameters: the reduced temperature t = T/T c 0 and the ratio between the T = 0 value of the chemical potential and the critical temperature T c 0 for Bose-Einstein condensation. Comparisons with first experimental results and ab-initio calculations are presented.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 109 (1997), S. 309-355 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the thermodynamic behaviour of a Bose gas interacting with repulsive forces and confined in a harmonic anisotropic trap. We develop the formalism of mean field theory for non uniform systems at finite temperature, based on the generalization of Bogoliubov theory for uniform gases. By employing the WKB semiclassical approximation for the excited states we derive systematic results for the temperature dependence of various thermodynamic quantities: condensate fraction, density profiles, thermal energy, specific heat and moment of inertia. Our analysis points out important differences with respect to the thermodynamic behaviour of uniform Bose gases. This is mainly the consequence of a major role played by single particle states at the boundary of the condensate. We find that the thermal depletion of the condensate is strongly enhanced by the presence of repulsive interactions and that the critical temperature is decreased with respect to the predictions of the non-interacting model. Our work points out an important scaling behaviour exhibited by the system in largeN limit. Scaling permits to express all the relevant thermodynamic quantities in terms of only two parameters: the reduced temperaturet=T/T c 0 and the ratio between theT=0 value of the chemical potential and the critical temperatureT c 0 for Bose-Einstein condensation. Comparisons with first experimental results and ab-initio calculations are presented.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 110 (1998), S. 449-454 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the scattering of atoms, rotons and phonons at the free surface of superfluid 4 He. We calculate the evaporation, condensation and reflection probabilities in the framework of linearized time dependent density functional theory accounting for elastic one-to-one processes. We explore the angular dependence of the scattering probabilities showing that most results are independent of the incidence angle and can be expressed in terms of a single energy dependent parameter.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 104 (1996), S. 367-397 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The scattering of atoms and rotons at the free surface of superfluid4He is studied in the framework of linearised time dependent mean field theory. The phenomenological Orsay-Trento density functional is used to solve numerically the equations of motion for the elementary excitations in presence of a free surface and to calculate the flux of rotons and atoms in the reflection, condensation, and evaporation processes. The probability associated with each process is evaluated as a function of energy, for incident angles such that only rotons and atoms are involved in the scattering (phonon forbidden region). The evaporation probability forR + rotons (positive group velocity) is predicted to increase quite rapidly from zero, near the roton minimum, to 1 as the energy increases. Conversely the evaporation fromR − rotons (negative group velocity) remains smaller than 0.25 for all energies. Close to the energy of the roton minimum, Δ, the mode-change processR + ↔R − is the dominant one. The consistency of the results with general properties of the scattering matrix, such as unitarity and time reversal, is explicitly discussed. The condensation of atoms into bulk excitations is also investigated. The condensation probability is almost 1 at high energy in agreement with experiments, but it lowers significantly when the energy approaches the roton minimum in the phonon forbidden region.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 107 (1997), S. 533-540 
    ISSN: 1573-7357
    Keywords: 74.20-z ; 74.25.kc ; 74.72.h
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider the phonon-mediated BCS mechanism for superconductivity. We show that in a material with a very large ionic dielectric constant, the maximum Tc is increased by an order-of-magnitude over the value in “conventional” metals, for a 2-D metal. This model applies to cuprates and organic metals.
    Type of Medium: Electronic Resource
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