97 research outputs found
Normal solution to the Enskog-Landau kinetic equation. Boundary conditions method
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
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
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
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
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
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
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
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
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 GeV
Identified mid-rapidity particle spectra of , , and
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 () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of 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/
- …