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Particle diffusion in rotating drums is studied via computer simulations using a full 3-D model which does not involve any arbitrary input parameters. The diffusion coefficient for single-component systems agree qualitatively with previous…

Condensed Matter · Physics 2009-10-28 G. A. Kohring

The transport of charged particles in various astrophysical environments permeated by magnetic fields is described in terms of a diffusion process, which relies on diffusion-tensor parameters generally inferred from Monte-Carlo simulations.…

High Energy Astrophysical Phenomena · Physics 2022-12-09 Olivier Deligny

We investigate test-particle diffusion in dynamical turbulence based on a numerical approach presented before. For the turbulence we employ the nonlinear anisotropic dynamical turbulence model which takes into account wave propagation…

High Energy Astrophysical Phenomena · Physics 2016-09-28 Martin Heusen , Andreas Shalchi

Cross-diffusion systems arise as hydrodynamic limits of lattice multi-species interacting particle models. The objective of this work is to provide a numerical scheme for the simulation of the cross-diffusion system identified in [J.…

Numerical Analysis · Mathematics 2023-09-06 Jad Dabaghi , Virginie Ehrlacher , Christoph Strössner

Understanding the transport of energetic cosmic rays belongs to the most challenging topics in astrophysics. Diffusion due to scattering by electromagnetic fluctuations is a key process in cosmic-ray transport. The transition from a…

High Energy Astrophysical Phenomena · Physics 2020-09-02 P. Reichherzer , J. Becker Tjus , E. G. Zweibel , L. Merten , M. J. Pueschel

Supernova remnants are expected to contain braided (or stochastic) magnetic fields, which are in some regions directed mainly perpendicular to the shock normal. For particle acceleration due to repeated shock crossings, the transport in the…

Astrophysics · Physics 2007-05-23 U. D. J. Gieseler , J. G. Kirk

The basics of focused transport as applied to solar energetic particles are reviewed, paying special attention to areas of common misconception. The micro-physics of charged particles interacting with slab turbulence are investigated to…

Space Physics · Physics 2020-12-15 J. P. van den Berg , R. D. Strauss , F. Effenberger

In this work, the Z-average, effective, apparent diffusion coefficients and their poly-dispersity indexes were investigated for dilute poly-disperse homogeneous spherical particles in dispersion where the Rayleigh-Gans-Debye approximation…

Chemical Physics · Physics 2007-05-23 Yong Sun

The Moliere theory of multiple Coulomb scattering is modified to take into account difference between scattering off atomic nuclei and electron. A simple analytical expression for angular distribution of charged particles passing through a…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. I. Striganov

We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle…

Astrophysics of Galaxies · Physics 2015-05-18 A. Beresnyak , H. Yan , A. Lazarian

Monte-Carlo (MC) methods, based on random updates and the trial-and-error principle, are well suited to retrieve particle size distributions from small-angle scattering patterns of dilute solutions of scatterers. The size sensitivity of…

Data Analysis, Statistics and Probability · Physics 2013-03-19 Brian Richard Pauw , Jan-Skov Pedersen , Samuel Tardif , Masaki Takata , Bo Brummersted Iversen

One key issue in the probability density function (PDF) approach for disperse two-phase turbulent flows is to close the diffusion term in the phase space. This study aimed to derive a kinetic equation for particle dispersion in turbulent…

Statistical Mechanics · Physics 2020-07-15 De-yu Zhong , Guang-qian Wang , Tie-jian Li , Ming-xi Zhang , You Xia

This work investigates the evolution of the distribution of charged particles due to the mechanism of stochastic turbulent acceleration (STA) in presence of small-scale turbulence with a mean magnetic field. STA is usually modelled as a…

High Energy Astrophysical Phenomena · Physics 2023-07-19 Sayan Kundu , Nishant Singh , Bhargav Vaidya

Monte Carlo simulation is one of the most important tools in the study of diffusion processes. For constant diffusion coefficients, an appropriate Gaussian distribution of particle's steplengths can generate exact results, when compared…

Computational Physics · Physics 2015-06-12 V. Ruiz Barlett , M. Hoyuelos , H. O. Mártin

Direct comparisons of diffusive particle acceleration numerical simulations have been made against Monte Carlo and hybrid plasma simulations by Ellison {\it et. al.} (1993) and against observations at the earth's bow shock presented by…

Astrophysics · Physics 2016-08-30 Hyesung Kang , T. W. Jones

The diffusion coefficient of a circular shaped inclusion in a liquid membrane is investigated by taking into account the interaction between membranes and bulk solvents of arbitrary thickness. As illustrative examples, the diffusion…

Soft Condensed Matter · Physics 2015-05-28 Kazuhiko Seki , Sanoop Ramachandran , Shigeyuki Komura

The Diffusion Monte Carlo method is devoted to the computation of electronic ground-state energies of molecules. In this paper, we focus on implementations of this method which consist in exploring the configuration space with a {\bf fixed}…

Numerical Analysis · Mathematics 2007-05-23 Tony Lelievre , Mohamed El Makrini , Benjamin Jourdain

Atmospheric turbulence is one of the lead disturbance factors for free-space quantum communication. The quantum states of light in such channels are affected by fluctuating losses characterized by the probability distribution of…

Quantum Physics · Physics 2023-10-02 M. Klen , A. A. Semenov

Diffusion in an evolving environment is studied by continuos-time Monte Carlo simulations. Diffusion is modelled by continuos-time random walkers on a lattice, in a dynamic environment provided by bubbles between two one-dimensional…

Soft Condensed Matter · Physics 2010-11-22 Janne Juntunen , Juha Merikoski

We discuss the efficiency of Monte Carlo methods in solving continuum radiative transfer problems. The sampling of the radiation field and convergence of dust temperature calculations in the case of optically thick clouds are both studied.…

Astrophysics · Physics 2009-11-10 M. Juvela