SYNERGETIC MITIGATION OF THE RAYLEIGH—TAYLOR INSTABILITY BY SHEAR AXIAL FLOWS AND FINITE LARMOR RADIUS

1　IntroductionImplodingZ pinchesemployinggaspuffs,cy lindricalfoils,andwirearraysareverycompactandefficientdevicesforcouplingelectromagneticenergyfromapulseforminglineintoadenseplas macolumn.Morerecently,aluminumwirearrayimplosionshaveproducedthehighestX raypowerof40TWonthe20TWSaturnacceleratoratSandiaNationalLaboratory[1].Thesedeviceshavepoten tialapplicationstocontrolledfusionaswellastointensesourcesofkeVX raysfornuclearweaponseffects.Unfortunately,theimplosionsarehighlysusceptibletoR…     

Complexity analysis and mathematical tools towards the modelling of living systems

This paper is a review and critical analysis of the mathematical kinetic theory of active particles applied to the modelling of large living systems made up of interacting entities. The first part of the paper is focused on a general presentation of the mathematical tools of the kinetic theory of active particles. The second part provides a review of a variety of mathematical models in life sciences, namely complex social systems, opinion formation, evolution of epidemics with virus mutations, and vehicular traffic, crowds and swarms. All the applications are technically related to the mathematical structures reviewed in the first part of the paper. The overall contents are based on the concept that living systems, unlike the inert matter, have the ability to develop behaviour geared towards their survival, or simply to improve the quality of their life. In some cases, the behaviour evolves in time and generates destructive and/or proliferative events.     

On the derivation of linearized hydrodynamics from kinetic theory

The relation of the linearized hydrodynamic equations to kinetic theory is discussed. We show that the theory of subdynamics provides a general framework for their derivation. This theory and the related transformation theory permit the construction of a Lyapounov functional that for the hydrodynamical processes, considered here, becomes the macroscopic entropy as given by Gibbs relation.     

Detectable states,cycle fluxes,and motility scaling of molecular motor kinesin: An integrative kinetic graph theory analysis

The process by which a kinesin motor couples its ATPase activity with concerted mechanical hand-over-hand steps is a foremost topic of molecular motor physics. Two major routes toward elucidating kinesin mechanisms are the motility performance characterization of velocity and run length, and single-molecular state detection experiments. However, these two sets of experimental approaches are largely uncoupled to date. Here, we introduce an integrative motility state analysis based on a theorized kinetic graph theory for kinesin, which, on one hand, is validated by a wealth of accumulated motility data, and, on the other hand, allows for rigorous quantification of state occurrences and chemomechanical cycling probabilities. An interesting linear scaling for kinesin motility performance across species is discussed as well. An integrative kinetic graph theory analysis provides a powerful tool to bridge motility and state characterization experiments, so as to forge a unified effort for the elucidation of the working mechanisms of molecular motors.     

Global Wave Solution of generalized MHD Equations in a Cylindrical Plasma

The linear eigenstate problem of generalized magnetohydrodynamics(MHD) equations in a cylindrical plasma is discussed. The effects of finite frequency and finite pressure perturbation lead to an important result: the resonant layer of the shear Alfven waves is not a singular layer. In this paper, the MHD equations are reduced to four differential equations of first order for perturbed quantities. An analytical dispersion relation for a homogeneous plasma cylinder is obtained. The K. Appert theory is a limiting case of our theory     

量子等离子体中波的色散关系以及朗道阻尼

利用动理学理论研究量子等离子体中波的色散关系和电子朗道阻尼.从电子的量子流体动力学方程和动理学描述下的光子运动方程出发,研究量子效应对光子朗道阻尼的修正.研究发现量子效应只对纵波模式,即电子等离子体波的色散关系有修正,对横向电磁波的色散关系没有影响.量子效应减小了朗道阻尼,起着朗道增长的作用. 关键词： 量子等离子体 朗道阻尼 电子等离子体波 色散关系     

Dispersion relation of excitation mode in strongly interacting fermions matter

This paper analyses the dispersion relation of the excitation mode in non-relativistic interacting fermion matter. The polarization tensor is calculated with the random phase approximation in terms of finite temperature field theory. With the polarization tensor, the influences of temperature, particle number density and interaction strength on the dispersion relation are discussed in detail. It finds that the collective effects are qualitatively more important in the unitary fermions than those in the finite contact interaction matter.     

Harmonic Fields in a Non Uniform Plasma

The magnitudes of the harmonic fields which are generated when an alternating electric field is applied to a plasma are calculated. The plasma has a density gradient and is immersed in a uniform static magnetic field. The harmonics are very strongly excited near the upper hybrid frequency. A fluid theory is employed to describe the highly non linear behavior near resonance and a kinetic theory is used to find the effect of a finite temperature. It is found that kinetic effects are important if the radius of gyration is comparable in size to the scale length.     

Kinetic theory of dense fluids

A kinetic theory of dense fluids is presented in this series of papers. The theory is based on a kinetic equation for subsystems which represents a subset of equations structurally invariant to the sizes of the subsystem that includes the Boltzmann equation as an element at the low density limit. There exists a H-function for the kinetic equation and the equilibrium solution is uniquely given by the canonical distribution functions for the subsystems comprising the entire system. The cluster expansion is discussed for the N-body collision operator appearing in the kinetic equation. The kinetic parts of transport coefficients are obtained by means of a moment method and their density expansions are formally obtained. The Chapman-Enskog method is discussed in the subsequent paper.     

Measurements of the shear Alfvén wave dispersion for finite perpendicular wave number

Measurements of the dispersion relation for shear Alfvén waves as a function of the perpendicular wave number are reported for the regime in which V(A) approximately V(Te). By measuring the parallel phase velocity of the waves, the measurements can be compared directly to theoretical predictions of the dispersion relation for a parameter regime in which particle kinetic effects become important. The comparison shows that the best agreement between theory and experiment is achieved when a fully complex, warm plasma dispersion relation is used.     

Kinetic instability of twisted ion-acoustic mode with superthermal species of plasma

The electrostatic twisted ion-acoustic waves with finite orbital angular momentum states and associated kinetic instability are investigated in an electron-ion plasma. The plasma consisting of superthermal electrons and ions is modeled by using a non-gyrotropic Kappa distribution function in which the free energy source for wave excitation is provided by the relative directed motion of streaming electrons with respect to the ions. In the frame work of kinetic theory, the Vlasov-Poisson equations are employed to derive the expressions for dispersion relation and Landau damping rate under paraxial approximation. The results are analyzed for threshold condition of wave dispersion and instability growth rate in the presence of helical electric field structure. The relevance of study to the observed situations is also described.     

Nuclear spin response to inelastic proton scattering: Finite geometry and absorption effects

Recent experiments have clearly demonstrated the ability of inelastic proton scattering to act as a precise probe of the nuclear spin response. Previous calculations based on infinite or semi-infinite matter models differ markedly from experiment in their prediction of longitudinal to transverse response function ratios. The present work indicates that finite geometry and absorption effects are crucial in bringing predictions closer to experiment. The effect of including isobar excitations is also investigated and assessed critically.     

Internal solitons in laboratory experiments: comparison with theoretical models

Nonlinear internal solitary waves observed in laboratory experiments are discussed from the standpoint of their relation to different soliton theories, from the classical integrable models such as the Korteweg-de Vries, Gardner, Benjamin-Ono, and Joseph-Kubota-Ko-Dobbs equations and their modifications, through the nonintegrable models describing higher-order nonlinear effects, viscosity, rotation, and cylindrical spreading, to the strongly nonlinear models. First, these theoretical models are briefly described and, then, laboratory data and their comparison with the theory are presented.     

Fermi hypernetted chain calculations in a periodic box

The Fermi hypernetted chain theory is reformulated to perform calculations with a finite number of fermions in a periodic box. The proposed method is expected to be useful to estimate the finite size effects in Quantum Monte Carlo simulations. Moreover, it can deal with anisotropic correlations as well as with different shaped boxes. Results are given for the neutron matter Bethe homework Hamiltonian and for nuclear matter with spin–isospin dependent central interactions. It is found that finite size effects come from both the kinetic and the potential energy expectation values.     

Homogeneous nucleation and growth of droplets in vapours

The theory of homogeneous nucleation of liquid drops in supersaturated vapours is reviewed. A new kinetic treatment which accounts for the heating of the growing clusters due to the latent heat of condensation is presented, and the irreversible thermodynamics of non-isothermal nucleation discussed. It is found that growing clusters are generally colder than the surrounding vapour during their sub-critical growth period.

Time dependent nucleation is discussed and a simple estimate for the time-lag in establishing the steady state is given. The nucleation in cloud chambers expanding with constant speed is discussed in detail, and the number of droplets formed and their final mean size is calculated as a function of the terminal expansion ratio. Re-evaporation of nucleated clusters is discussed. Numerical results are given for a number of typical situations in experiments on water-vapour. These results for the nucleation rate as corrected by Lothe and Pound predict much lower ‘critical’ expansion ratios than indicated by the limited experimental data available, even when the non-isothermal theory is used.

To restore agreement between theory and experiments the surface tension for small droplets (?100 molecules) could be increased some 15% above that of the bulk liquid, or the pre-exponential in the nucleation rate could be decreased by some 10^?15. This latter expedient roughly corresponds to use of the ‘classical’ instead of the Lothe-Pound nucleation rate. These two alterations would, however, affect the theoretical curves in different manners and careful experiments could possibly distinguish between them.     

Photonuclear data and modern physics of giant resonances

The results of the development (“renaissance”) of giant-resonance physics are briefly discussed from the point of view of their application to creating a photonuclear database. It is indicated that part of the recommendations from corresponding libraries of data are not at the level of the present-day status of giant-resonance physics. A Lorentzian parametrization of the most reliable experimental data on isovector M1 resonances is constructed for seven spherical nuclei, and it is shown that the widths of M1 resonances are severalfold, sometimes an order of magnitude, smaller than the value of Γ₀ = 4 MeV, which was recommended for all nuclei. The need for microscopically taking into account configurations more complex than those that are included within the standard random-phase approximation or within the quasiparticle random-phase approximation is emphasized. To be more precise, it is necessary to take into account coupling to phonons, since this changes the temperature dependence of the resonance width in relation to that which was used earlier and since, without this, one cannot explain the properties of pygmy dipole resonances in the region of the nucleon binding energy. Our calculations of the average energies of the pygmy dipole resonances in the Ca and Sn isotopes within the microscopic extended theory of finite Fermi systems reveal that the inclusion of coupling to phonons reduces these energies considerably toward the improvement of agreement with experimental data. The idea of creating a library of photonuclear data for unstable nuclei, including fission fragments, on the basis of the extended theory of finite Fermi systems is discussed in connection with the fact that information necessary for fitting the parameters of phenomenological theories is absent or insufficient for such nuclei.     

Brueckner theory of nuclei

This paper reviews developments of the Brueckner theory of nuclei, starting with the multiple-scattering approach in the 1954 papers of Brueckner et al. Inevitably, the presentation represents the authors personal view on the problems. Theories rather than calculations have been emphasized. The latter depend very much upon the two-nucleon interaction which is still not known in sufficient detail. The definition of the Brueckner reaction-matrix is discussed at some length with regard to insertions in hole- and particle-lines. Löwdin's Exact Self-Consistent-Field theory that provides an exact many-body reaction matrix is given a short presentation for comparison with Brueckner's theory as applied to finite nuclei. Considerable attention has been given to the shell-model potential required for calculations on finite nuclei. The concept of single-particle energies is discussed in some detail in relation to removal energies. Some numerical results are reviewed either for illustrating the theory or because they are recent.