摘要:

The Maxwellian distribution known as the one‐particle equilibrium solution is generalized to the two‐particle regime where homogeneous macroscopic fluctuations in the density, the velocity, and the temperature prevail. The equilibrium distribution has the form of a bimodal Maxwellian, namely, the average of two Maxwellians with thermodynamic parameters greater and smaller than the mean values by the root‐mean‐squared fluctuations. This result is shown to hold for monatomic gases with arbitrary intermolecular potentials. Turbulent reaction rate calculated with this distribution can be by the order of magnitude large compared with the Arrhenius law, in other words, far beyond the first order smallness of the temperature fluctuation if the activation energy is sufficiently high.

ISSN:0031-9171    

DOI:10.1063/1.863673

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Evaporation and condensation of vapor‐gas mixture is studied on the basis of the kinetic BGK–Morse model equation. The linearized kinetic model equation is solved using the half‐range Hermite polynomials and various slip coefficients are obtained. The obtained slip coefficient of vapor pressure is insensitive to the variation in concentration of a noncondensable gas. When the mean concentration of noncondensable gas is very small, an exponential distribution of noncondensable gas is obtained and a set of nonlinear equations is transformed to that of linear equations for pure vapor. It is found from the linear and nonlinear solutions that the impedance of mass flux in the two‐surface problem is composed of surface and induced resistances and that the latter is proportional to the total amount of the noncondensable gas rather than the mean concentration of it.

ISSN:0031-9171    

DOI:10.1063/1.863674

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The diffusion of certain test particles that in the presence of an external constant conservative force, undergo collisions against the field particles of an infinite homogeneous host medium as well as between themselves, is studied on the basis of an integral reformulation of the relevant stationary spatially‐independent nonlinear integrodifferential Boltzmann equation. The existence and uniqueness of the solution for the distribution function of the test particles considered is investigated by an application of the contracting mapping principle for both the general nonlinear case and for the linearized one as resulting through an appropriate decomposition of the sought distribution function. Also, the case when the scattering probability is represented as a factorized expansion of finite rank is discussed in some detail.

ISSN:0031-9171    

DOI:10.1063/1.863675

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The canonical Poisson structure of the microscopic Lagrangian is used to deduce the noncanonical Poisson structure for the macroscopic Hamiltonian dynamics of a compressible neutral fluid and of fluid electrodynamics.

ISSN:0031-9171    

DOI:10.1063/1.863676

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The stability of a two‐dimensional magnetic model of a thick quasineutral sheet including a small but finite normal magnetic field component is studied in a collisionless plasma. Such a magnetic configuration allows an adiabatic motion for electrons which are trapped in good agreement with the thick sheet model. A detailed kinetic study of the energy balance shows that the ion linear tearing mode instability is suppressed by the interaction between the perturbed electromagnetic field and the adiabatic electron motion; this interaction leads to a ‘‘compressibility’’ effect which prevents the instability onset. The connection with the magnetohydrodynamic energy principle for stability is demonstrated. A general formalism is developed for any magnetic configuration and applied to a parabolic and a magnetic island topology. Some conclusions concerning the nonlinear tearing mode behavior (explosive phase) are drawn.

ISSN:0031-9171    

DOI:10.1063/1.863677

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The nonlinear interaction of the drift cyclotron and lower‐hybrid‐drift modes is examined. A renormalized equation for the drift cyclotron ion response is derived and solved. Lower‐hybrid‐drift modes comprise the turbulent background. For levels of lower‐hybrid‐drift turbulence ofe&Fgr;/Ti∼(me/mi)1/2(&rgr;i/L)3/4, the growth rate of the drift cyclotron mode begins to be reduced by ion cyclotron resonance broadening, which is the dominant nonlinear effect.

ISSN:0031-9171    

DOI:10.1063/1.863678

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The problem of the nonlinear filamentation of lower‐hybrid waves in a two‐ion species magnetized plasma has been investigated. The dominant nonlinear effect comes from the existence of two ion species if the concentration of second ion species is larger than (me/mi)s−1(with 1<s<3/2). The nonlinear Schro¨dinger equation and the modified nonlinear Schro¨dinger equation describing the nonlinear self‐distortion of the propagation cones of lower‐hybrid waves due to the interaction with low‐frequency ion‐ion hybrid perturbations are derived for the case of fast phase variation. In the case of slow phase variation the nonlinear self‐distortion of the propagation cones of lower‐hybrid waves is described by the modified Korteweg–deVries equation when the ion‐ion wave is at the Buschbaum frequency. The nonlinear equation which governs the asymptotic state of filamentation admits an exact solution, describing solitons, envelope solitons, or cusped envelope solitons for the electric field. These solitons represent the nonlinear stage of the evolution of the purely growing mode which appears in the parametric analysis.

ISSN:0031-9171    

DOI:10.1063/1.863689

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A radial normal mode analysis is carried out to study the stability of fluidlike flute modes in a simplified model of the ELMO Bumpy Torus. The corresponding stability conditions are obtained.

ISSN:0031-9171    

DOI:10.1063/1.863690

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The equilibrium magnetic field of a bumpy torus confinement system is analyzed by expansion in the inverse aspect ratio. Decomposition of the plasma volume into low‐beta and high‐beta regions permits the derivation of relatively explicit formulas, which should be useful in bumpy torus transport and stability studies. In the low‐beta regions, which typically occupy most of the plasma volume, the magnetic field is computed through first order in the inverse aspect ratio, including plasma pressure correction terms. The high‐beta region is treated in a scalar pressure, thin‐ring approximation, without toroidal corrections; connection formulas for the change in flux‐surface geometry across the high‐beta annulus are obtained, together with an expression for the field inside the annulus. The analysis of both regions is completely general with respect to bump amplitude and bump shape.

ISSN:0031-9171    

DOI:10.1063/1.863691

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A variational principle formulation is used to calculate the electron radial transport coefficients in a nonaxisymmetric tandem mirror, in the low collisionality regime. Explicit analytical estimates are given for two important classes of electrons. The implications of symmetry, end currents, and ambipolarity are discussed in detail in order to demonstrate their potentially important effect on the radial particle loss rates.

ISSN:0031-9171    

DOI:10.1063/1.863692

出版商:AIP    

年代:1982

数据来源: AIP