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We study the transport of self-propelled particles in dynamic complex environments. To obtain exact results, we introduce a model of run-and-tumble particles (RTPs) moving in discrete time on a $d$-dimensional cubic lattice in the presence…

Statistical Mechanics · Physics 2018-07-12 Thibault Bertrand , Yongfeng Zhao , Olivier Bénichou , Julien Tailleur , Raphaël Voituriez

Diffusion models cannot enforce hard constraints, yet applications in the physical sciences demand exact satisfaction of conservation laws, boundary conditions, and observational consistency. In this work, we identify a corrector kernel…

Machine Learning · Computer Science 2026-05-14 Omer Rochman-Sharabi , Gilles Louppe

We describe a novel approach to statistical learning from particles tracked while moving in a random environment. The problem consists in inferring properties of the environment from recorded snapshots. We consider here the case of a fluid…

Information Theory · Computer Science 2008-06-09 Michael Chertkov , Lukas Kroc , Massimo Vergassola

The transport of energetic particles such as Cosmic Rays is governed by the properties of the plasma being traversed. While these properties are rather poorly known for galactic and interstellar plasmas due to the lack of in situ…

Solar and Stellar Astrophysics · Physics 2014-06-03 Tobias Wiengarten , Jens Kleimann , Horst Fichtner , Patrick Kühl , Andreas Kopp , Bernd Heber , Ralf Kissmann

Current-day cosmic ray (CR) propagation studies use static Milky-Way models and fit parametrized source distributions to data. Instead, we use three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies with the…

High Energy Astrophysical Phenomena · Physics 2021-05-25 Maria Werhahn , Christoph Pfrommer , Philipp Girichidis , Ewald Puchwein , Rüdiger Pakmor

Energetic particle transport in a finite amplitude magnetosonic and Alfvenic turbulence is considered using Monte Carlo particle simulations, which involve an integration of particle equation of motion. We show that in a low-Betha plasma…

Astrophysics · Physics 2008-02-03 G. Michalek , M. Ostrowski , R. Schlickeiser

Models for the transport of high energy charged particles through strong magnetic turbulence play a key role in space and astrophysical studies, such as describing the propagation of solar energetic particles and high energy cosmic rays.…

We study transport of GeV cosmic rays (CRs) in a set of high-resolution TIGRESS magnetohydrodynamic simulations of the star-forming interstellar medium (ISM). Our local disk patch models sample a wide range of gas surface densities,…

Astrophysics of Galaxies · Physics 2025-09-04 Ronan Hix , Lucia Armillotta , Eve Ostriker , Chang-Goo Kim

Heterogeneous media diffusion is often described using position-dependent diffusion coefficients and estimated indirectly through mean squared displacement in experiments. This approach may overlook other mechanisms and their interaction…

Statistical Mechanics · Physics 2023-09-11 Haroldo V. Ribeiro , Angel A. Tateishi , Ervin K. Lenzi , Richard L. Magin , Matjaz Perc

Transport surrounding is full of all kinds of fields, like particle potential, external potential. Under these conditions, how elements work and how position and momentum redistribute in the diffusion? For enriching the Fick law in…

Soft Condensed Matter · Physics 2017-08-02 Jian-hui He , Jia-le Wen , Pei-rong Chen , Dong-qin Zheng , Wei-rong Zhong

Energetic particle redistribution in the presence of multiple Alfv\'en eigenmodes is analyzed in [PPCF 58, 014019 (2016)] for the ITER 15MA baseline scenario: non-linear hybrid simulations (within their well known limits) point out that…

Plasma Physics · Physics 2022-11-17 Nakia Carlevaro , Giovanni Montani , Matteo Valerio Falessi , Philipp Lauber

Interacting particles diffusing in single-file is a fundamental model of transport in narrow channels where particles cannot bypass each other. An important result has been obtained by Kollmann [Phys. Rev. Lett. 90, 180602 (2003)] for the…

Statistical Mechanics · Physics 2025-07-24 Théotim Berlioz , Olivier Bénichou , Aurélien Grabsch

Radio applications are increasingly being used in urban environments for cellular radio systems and safety applications that use vehicle-vehicle, and vehicle-to-infrastructure. We present a novel ray tracing-based radio propagation…

Signal Processing · Electrical Eng. & Systems 2023-05-16 Ruichen Wang , Dinesh Manocha

The periodic Lorentz gas is a paradigmatic model to examine how macroscopic transport emerges from microscopic chaos. It consists of a triangular lattice of circular hard scatterers with a moving point particle. Recently this system became…

Statistical Mechanics · Physics 2019-05-30 S. Gil-Gallegos , R. Klages , J. Solanpää , E. Räsänen

Transport of point-size Brownian particles under the influence of a constant and uniform force field through a three-dimensional channel with smoothly varying periodic cross-section is investigated. Here, we employ an asymptotic analysis in…

Statistical Mechanics · Physics 2011-07-14 Steffen Martens , Gerhard Schmid , Lutz Schimansky-Geier , Peter Hänggi

We show that the Turing patterns in reaction systems with subdiffusion can be replicated in an effective system with Markovian cross-diffusion. The effective system has the same Turing instability as the original system, and the same…

Pattern Formation and Solitons · Physics 2020-01-29 Joseph W. Baron , Tobias Galla

Galactic cosmic rays are a ubiquitous source of ionisation of the interstellar gas, competing with UV and X-ray photons as well as natural radioactivity in determining the fractional abundance of electrons, ions and charged dust grains in…

High Energy Astrophysical Phenomena · Physics 2018-06-27 Marco Padovani , Alexei V. Ivlev , Daniele Galli , Paola Caselli

There is no single mechanism by which fast particles are accelerated in astrophysical environments, and it is now recognized that the data require a rich variety of different mechanisms operating under different conditions. The mechanisms…

High Energy Astrophysical Phenomena · Physics 2011-07-15 Elisabete M. de Gouveia Dal Pino , Grzegorz Kowal , Alex Lazarian , Reinaldo Santos-Lima

Cosmic ray propagation is determined by the properties of interstellar turbulence. The multiphase nature of interstellar medium (ISM) and diversity of driving mechanisms give rise to spatial variation of turbulence properties. Meanwhile,…

High Energy Astrophysical Phenomena · Physics 2021-09-21 Huirong Yan

We aim to elucidate cosmic ray (CR) propagation in the weakly ionized environments of supernova remnants (SNRs) basing our analysis on the cosmic ray cloud (CRC) model developed by \citet{2013ApJ...768...73M} and…

High Energy Astrophysical Phenomena · Physics 2020-01-15 L. Brahimi , A. Marcowith , V. S. Ptuskin