97 research outputs found

    Normal solution to the Enskog-Landau kinetic equation. Boundary conditions method

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    Nonstationary and nonequilibrium processes are considered on the basis of an Enskog-Landau kinetic equation using a boundary conditions method. A nonstationary solution of this equation is found in the pair collision approximation. This solution takes into account explicitly the influence of long-range interactions. New terms to the transport coefficients are identified. An application of the boundary conditions method to hydrodynamic description of fast processes is discussed.Comment: 11 LaTeX pages using Elsevier format elsart.st

    Enskog-Landau kinetic equation. Calculation of the transport coefficients for charged hard spheres

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    Using charged hard spheres model as an example, the dense one-component plasma is considered. For this model the Enskog-Landau kinetic equation is obtained and its normal solution is found using the Chapman-Enskog method. Transport coefficients are obtained numerically and analytically and compared with the experimental data available.Comment: 13 LaTeX209 pages, 4 figures (emline-format for LaTeX

    Investigation of transfer coefficients for many-component dense systems of neutral and charged hard spheres

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    In present work a calculation of transfer coefficients for many-component dense gases for charged and non-charged hard spheres is carried out using the Enskog-Landau kinetic equation which takes into account realistic particle sizes.Comment: 4 pages, 2 eps-figure

    Controlled Global Ganymede Mosaic from Voyager and Galileo Images

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    In preparation of the JUICE mission with the primary target Ganymede we generated a new controlled version of the global Ganymede image mosaic using a combination of Voyager 1 and 2 and Galileo images. Baseline for this work was the new 3D control point network from Zubarev et al., 2016, which uses the best available images from both missions and led to new position and pointing of the images. Creating a global mosaic with these corrected images made it reasonable to decide for a higher map scale of the global mosaic as currently existing ones. Therefore, we included very high-resolved Galileo images that cover only a few percent of the surface but can be analyzed directly within their surrounding context. As a consequence, it supports the JUICE operations team during the planning of the Ganymede orbit phase at the end of the mission (Grasset et al., 2013)

    Updated Ganymede Mosaic from Voyager and Galileo Observations

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    In preparation of the JUICE mission with the primary target Ganymede [1] we generated a new controlled version of the global Ganymede image mosaic using a combination of Voyager 1 and 2 and Galileo images. Baseline for this work was the new 3D control point network from Zubarev et al., 2016, which uses the best available images from both missions and led to new position and pointing of the images

    Normal solution and transport coefficients to the Enskog-Landau kinetic equation for a two-component system of charged hard spheres. The Chapman-Enskog method

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    An Enskog-Landau kinetic equation for a many-component system of charged hard spheres is proposed. It has been obtained from the Liouville equation with modified boundary conditions by the method of nonequilibrium statistical operator. On the basis of this equation the normal solutions and transport coefficients such as bulk kappa and shear eta viscosities, thermal conductivity lambda, mutual diffusion D^{\alpha\beta} and thermal diffusion D_T^\alpha have been obtained for a binary mixture in the first approximation using the Chapman-Enskog method. Numerical calculations of all transport coefficients for mixtures Ar-Kr, Ar-Xe, Kr-Xe with different concentrations of compounds have been evaluated for the cases of absence and presence of long-range Coulomb interactions. The results are compared with those obtained from other theories and experiment.Comment: 24 LaTeX209 pages, 3 EPS figures (4 files). To be published in Physica

    Updated Ganymede Mosaic from Juno Perijove 34 Images

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    In preparation of the JUICE mission with the primary target Ganymede we generated a new controlled version of the global Ganymede image mosaic from Voyager 1 and 2, Galileo, and Juno images

    An optimization principle for deriving nonequilibrium statistical models of Hamiltonian dynamics

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    A general method for deriving closed reduced models of Hamiltonian dynamical systems is developed using techniques from optimization and statistical estimation. As in standard projection operator methods, a set of resolved variables is selected to capture the slow, macroscopic behavior of the system, and the family of quasi-equilibrium probability densities on phase space corresponding to these resolved variables is employed as a statistical model. The macroscopic dynamics of the mean resolved variables is determined by optimizing over paths of these probability densities. Specifically, a cost function is introduced that quantifies the lack-of-fit of such paths to the underlying microscopic dynamics; it is an ensemble-averaged, squared-norm of the residual that results from submitting a path of trial densities to the Liouville equation. The evolution of the macrostate is estimated by minimizing the time integral of the cost function. The value function for this optimization satisfies the associated Hamilton-Jacobi equation, and it determines the optimal relation between the statistical parameters and the irreversible fluxes of the resolved variables, thereby closing the reduced dynamics. The resulting equations for the macroscopic variables have the generic form of governing equations for nonequilibrium thermodynamics, and they furnish a rational extension of the classical equations of linear irreversible thermodynamics beyond the near-equilibrium regime. In particular, the value function is a thermodynamic potential that extends the classical dissipation function and supplies the nonlinear relation between thermodynamics forces and fluxes

    Quantum stochastic differential equations for boson and fermion systems -- Method of Non-Equilibrium Thermo Field Dynamics

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    A unified canonical operator formalism for quantum stochastic differential equations, including the quantum stochastic Liouville equation and the quantum Langevin equation both of the It\^o and the Stratonovich types, is presented within the framework of Non-Equilibrium Thermo Field Dynamics (NETFD). It is performed by introducing an appropriate martingale operator in the Schr\"odinger and the Heisenberg representations with fermionic and bosonic Brownian motions. In order to decide the double tilde conjugation rule and the thermal state conditions for fermions, a generalization of the system consisting of a vector field and Faddeev-Popov ghosts to dissipative open situations is carried out within NETFD.Comment: 69 page

    Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    Identified mid-rapidity particle spectra of π±\pi^{\pm}, K±K^{\pm}, and p(pˉ)p(\bar{p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (RdAuR_{dAu}) between protons (p+pˉ)(p+\bar{p}) and charged hadrons (hh) in the transverse momentum range 1.2<pT<3.01.2<{p_{T}}<3.0 GeV/c is measured to be 1.19±0.051.19\pm0.05(stat)±0.03\pm0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p+pˉ)/h(p+\bar{p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/
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